Functions, operators, and conditionals in GoogleSQL

GoogleSQL is the new name for Google Standard SQL! New name, same great SQL dialect.

This topic is a compilation of functions, operators, and conditional expressions.

To learn more about how to call functions, function call rules, the SAFE prefix, and special types of arguments, see Function calls.

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OPERATORS AND CONDITIONALS

Operators in GoogleSQL

GoogleSQL for Spanner supports operators. Operators are represented by special characters or keywords; they do not use function call syntax. An operator manipulates any number of data inputs, also called operands, and returns a result.

Common conventions:

• Unless otherwise specified, all operators return NULL when one of the operands is NULL.
• All operators will throw an error if the computation result overflows.
• For all floating point operations, +/-inf and NaN may only be returned if one of the operands is +/-inf or NaN. In other cases, an error is returned.

Operator precedence

The following table lists all GoogleSQL operators from highest to lowest precedence, i.e. the order in which they will be evaluated within a statement.

Order of Precedence	Operator	Input Data Types	Name	Operator Arity
1	Field access operator	JSON STRUCT	Field access operator	Binary
	Array subscript operator	ARRAY	Array position. Must be used with OFFSET or ORDINAL—see Array Functions .	Binary
	JSON subscript operator	JSON	Field name or array position in JSON.	Binary
2	+	All numeric types	Unary plus	Unary
	-	All numeric types	Unary minus	Unary
	~	Integer or BYTES	Bitwise not	Unary
3	*	All numeric types	Multiplication	Binary
	/	All numeric types	Division	Binary
	||	STRING, BYTES, or ARRAY<T>	Concatenation operator	Binary
4	+	All numeric types	Addition	Binary
	-	All numeric types	Subtraction	Binary
5	<<	Integer or BYTES	Bitwise left-shift	Binary
	>>	Integer or BYTES	Bitwise right-shift	Binary
6	&	Integer or BYTES	Bitwise and	Binary
7	^	Integer or BYTES	Bitwise xor	Binary
8	|	Integer or BYTES	Bitwise or	Binary
9 (Comparison Operators)	=	Any comparable type. See Data Types for a complete list.	Equal	Binary
	<	Any comparable type. See Data Types for a complete list.	Less than	Binary
	>	Any comparable type. See Data Types for a complete list.	Greater than	Binary
	<=	Any comparable type. See Data Types for a complete list.	Less than or equal to	Binary
	>=	Any comparable type. See Data Types for a complete list.	Greater than or equal to	Binary
	!=, <>	Any comparable type. See Data Types for a complete list.	Not equal	Binary
	[NOT] LIKE	STRING and BYTES	Value does [not] match the pattern specified	Binary
	[NOT] BETWEEN	Any comparable types. See Data Types for a complete list.	Value is [not] within the range specified	Binary
	[NOT] IN	Any comparable types. See Data Types for a complete list.	Value is [not] in the set of values specified	Binary
	IS [NOT] NULL	All	Value is [not] NULL	Unary
	IS [NOT] TRUE	BOOL	Value is [not] TRUE.	Unary
	IS [NOT] FALSE	BOOL	Value is [not] FALSE.	Unary
10	NOT	BOOL	Logical NOT	Unary
11	AND	BOOL	Logical AND	Binary
12	OR	BOOL	Logical OR	Binary

Operators with the same precedence are left associative. This means that those operators are grouped together starting from the left and moving right. For example, the expression:

x AND y AND z

is interpreted as

( ( x AND y ) AND z )

The expression:

x * y / z

is interpreted as:

( ( x * y ) / z )

All comparison operators have the same priority, but comparison operators are not associative. Therefore, parentheses are required in order to resolve ambiguity. For example:

(x < y) IS FALSE

Field access operator

expression.fieldname[. ...]

Description

Gets the value of a field. Alternatively known as the dot operator. Can be used to access nested fields. For example, expression.fieldname1.fieldname2.

Input values:

• STRUCT
• JSON

Return type

• For STRUCT: SQL data type of fieldname. If a field is not found in the struct, an error is thrown.
• For JSON: JSON. If a field is not found in a JSON value, a SQL NULL is returned.

Example

In the following example, the expression is t.customer and the field access operations are .address and .country. An operation is an application of an operator (.) to specific operands (in this case, address and country, or more specifically, t.customer and address, for the first operation, and t.customer.address and country for the second operation).

WITH orders AS (
  SELECT STRUCT(STRUCT('Yonge Street' AS street, 'Canada' AS country) AS address) AS customer
)
SELECT t.customer.address.country FROM orders AS t;

+---------+
| country |
+---------+
| Canada  |
+---------+

Array subscript operator

array_expression[array_subscript_specifier]

array_subscript_specifier:
  position_keyword(index)

position_keyword:
  { OFFSET | SAFE_OFFSET | ORDINAL | SAFE_ORDINAL }

Note: The brackets ([]) around array_subscript_specifier are part of the syntax; they do not represent an optional part.

Description

Gets a value from an array at a specific position.

Input values:

• array_expression: The input array.
• position_keyword(index): Determines where the index for the array should start and how out-of-range indexes are handled. The index is an integer that represents a specific position in the array.
  • OFFSET(index): The index starts at zero. Produces an error if the index is out of range.
  • SAFE_OFFSET(index): The index starts at zero. Returns NULL if the index is out of range.
  • ORDINAL(index): The index starts at one. Produces an error if the index is out of range.
  • SAFE_ORDINAL(index): The index starts at one. Returns NULL if the index is out of range.

Return type

T where array_expression is ARRAY<T>.

Examples

In following query, the array subscript operator is used to return values at specific position in item_array. This query also shows what happens when you reference an index (6) in an array that is out of range. If the SAFE prefix is included, NULL is returned, otherwise an error is produced.

WITH Items AS (SELECT ["coffee", "tea", "milk"] AS item_array)
SELECT
  item_array,
  item_array[OFFSET(0)] AS item_offset,
  item_array[ORDINAL(1)] AS item_ordinal,
  item_array[SAFE_OFFSET(6)] AS item_safe_offset
FROM Items

+---------------------+-------------+--------------+------------------+
| item_array          | item_offset | item_ordinal | item_safe_offset |
+---------------------+-------------+--------------+------------------+
| [coffee, tea, milk] | coffee      | coffee       | NULL             |
+---------------------+-------------+--------------+------------------+

When you reference an index that is out of range in an array, and a positional keyword that begins with SAFE is not included, an error is produced. For example:

WITH Items AS (SELECT ["coffee", "tea", "milk"] AS item_array)
SELECT
  item_array[OFFSET(6)] AS item_offset
FROM Items

-- Error. Array index 6 is out of bounds.

JSON subscript operator

json_expression[array_element_id]

json_expression[field_name]

Note: The brackets ([]) around array_element_id and field_name are part of the syntax; they do not represent an optional part.

Description

Gets a value of an array element or field in a JSON expression. Can be used to access nested data.

Input values:

• JSON expression: The JSON expression that contains an array element or field to return.
• [array_element_id]: An INT64 expression that represents a zero-based index in the array. If a negative value is entered, or the value is greater than or equal to the size of the array, or the JSON expression doesn't represent a JSON array, a SQL NULL is returned.
• [field_name]: A STRING expression that represents the name of a field in JSON. If the field name is not found, or the JSON expression is not a JSON object, a SQL NULL is returned.

Return type

JSON

Example

In the following example:

• json_value is a JSON expression.
• .class is a JSON field access.
• .students is a JSON field access.
• [0] is a JSON subscript expression with an element offset that accesses the zeroth element of an array in the JSON value.
• ['name'] is a JSON subscript expression with a field name that accesses a field.

SELECT json_value.class.students[0]['name'] AS first_student
FROM
  UNNEST(
    [
      JSON '{"class" : {"students" : [{"name" : "Jane"}]}}',
      JSON '{"class" : {"students" : []}}',
      JSON '{"class" : {"students" : [{"name" : "John"}, {"name": "Jamie"}]}}'])
    AS json_value;

+-----------------+
| first_student   |
+-----------------+
| "Jane"          |
| NULL            |
| "John"          |
+-----------------+

Arithmetic operators

All arithmetic operators accept input of numeric type T, and the result type has type T unless otherwise indicated in the description below:

Name	Syntax
Addition	X + Y
Subtraction	X - Y
Multiplication	X * Y
Division	X / Y
Unary Plus	+ X
Unary Minus	- X

NOTE: Divide by zero operations return an error. To return a different result, consider the IEEE_DIVIDE or SAFE_DIVIDE functions.

Result types for Addition, Subtraction and Multiplication:

INPUT	INT64	NUMERIC	FLOAT64
INT64	INT64	NUMERIC	FLOAT64
NUMERIC	NUMERIC	NUMERIC	FLOAT64
FLOAT64	FLOAT64	FLOAT64	FLOAT64

Result types for Division:

INPUT	INT64	NUMERIC	FLOAT64
INT64	FLOAT64	NUMERIC	FLOAT64
NUMERIC	NUMERIC	NUMERIC	FLOAT64
FLOAT64	FLOAT64	FLOAT64	FLOAT64

Result types for Unary Plus:

INPUT	INT64	NUMERIC	FLOAT64
OUTPUT	INT64	NUMERIC	FLOAT64

Result types for Unary Minus:

INPUT	INT64	NUMERIC	FLOAT64
OUTPUT	INT64	NUMERIC	FLOAT64

Bitwise operators

All bitwise operators return the same type and the same length as the first operand.

Name	Syntax	Input Data Type	Description
Bitwise not	~ X	Integer or BYTES	Performs logical negation on each bit, forming the ones' complement of the given binary value.
Bitwise or	X | Y	X: Integer or BYTES Y: Same type as X	Takes two bit patterns of equal length and performs the logical inclusive OR operation on each pair of the corresponding bits. This operator throws an error if X and Y are bytes of different lengths.
Bitwise xor	X ^ Y	X: Integer or BYTES Y: Same type as X	Takes two bit patterns of equal length and performs the logical exclusive OR operation on each pair of the corresponding bits. This operator throws an error if X and Y are bytes of different lengths.
Bitwise and	X & Y	X: Integer or BYTES Y: Same type as X	Takes two bit patterns of equal length and performs the logical AND operation on each pair of the corresponding bits. This operator throws an error if X and Y are bytes of different lengths.
Left shift	X << Y	X: Integer or BYTES Y: INT64	Shifts the first operand X to the left. This operator returns 0 or a byte sequence of b'\x00' if the second operand Y is greater than or equal to the bit length of the first operand X (for example, 64 if X has the type INT64). This operator throws an error if Y is negative.
Right shift	X >> Y	X: Integer or BYTES Y: INT64	Shifts the first operand X to the right. This operator does not do sign bit extension with a signed type (i.e. it fills vacant bits on the left with 0). This operator returns 0 or a byte sequence of b'\x00' if the second operand Y is greater than or equal to the bit length of the first operand X (for example, 64 if X has the type INT64). This operator throws an error if Y is negative.

Logical operators

GoogleSQL supports the AND, OR, and NOT logical operators. Logical operators allow only BOOL or NULL input and use three-valued logic to produce a result. The result can be TRUE, FALSE, or NULL:

x	y	x AND y	x OR y
TRUE	TRUE	TRUE	TRUE
TRUE	FALSE	FALSE	TRUE
TRUE	NULL	NULL	TRUE
FALSE	TRUE	FALSE	TRUE
FALSE	FALSE	FALSE	FALSE
FALSE	NULL	FALSE	NULL
NULL	TRUE	NULL	TRUE
NULL	FALSE	FALSE	NULL
NULL	NULL	NULL	NULL

x	NOT x
TRUE	FALSE
FALSE	TRUE
NULL	NULL

Examples

The examples in this section reference a table called entry_table:

+-------+
| entry |
+-------+
| a     |
| b     |
| c     |
| NULL  |
+-------+

SELECT 'a' FROM entry_table WHERE entry = 'a'

-- a => 'a' = 'a' => TRUE
-- b => 'b' = 'a' => FALSE
-- NULL => NULL = 'a' => NULL

+-------+
| entry |
+-------+
| a     |
+-------+

SELECT entry FROM entry_table WHERE NOT (entry = 'a')

-- a => NOT('a' = 'a') => NOT(TRUE) => FALSE
-- b => NOT('b' = 'a') => NOT(FALSE) => TRUE
-- NULL => NOT(NULL = 'a') => NOT(NULL) => NULL

+-------+
| entry |
+-------+
| b     |
| c     |
+-------+

SELECT entry FROM entry_table WHERE entry IS NULL

-- a => 'a' IS NULL => FALSE
-- b => 'b' IS NULL => FALSE
-- NULL => NULL IS NULL => TRUE

+-------+
| entry |
+-------+
| NULL  |
+-------+

Comparison operators

Comparisons always return BOOL. Comparisons generally require both operands to be of the same type. If operands are of different types, and if GoogleSQL can convert the values of those types to a common type without loss of precision, GoogleSQL will generally coerce them to that common type for the comparison; GoogleSQL will generally coerce literals to the type of non-literals, where present. Comparable data types are defined in Data Types.

Structs support only these comparison operators: equal (=), not equal (!= and <>), and IN.

The comparison operators in this section cannot be used to compare JSON GoogleSQL literals with other JSON GoogleSQL literals. If you need to compare values inside of JSON, convert the values to SQL values first. For more information, see JSON functions.

The following rules apply when comparing these data types:

• FLOAT64: All comparisons with NaN return FALSE, except for != and <>, which return TRUE.
• BOOL: FALSE is less than TRUE.
• STRING: Strings are compared codepoint-by-codepoint, which means that canonically equivalent strings are only guaranteed to compare as equal if they have been normalized first.
• NULL: The convention holds here: any operation with a NULL input returns NULL.

Name	Syntax	Description
Less Than	X < Y	Returns TRUE if X is less than Y.
Less Than or Equal To	X <= Y	Returns TRUE if X is less than or equal to Y.
Greater Than	X > Y	Returns TRUE if X is greater than Y.
Greater Than or Equal To	X >= Y	Returns TRUE if X is greater than or equal to Y.
Equal	X = Y	Returns TRUE if X is equal to Y.
Not Equal	X != Y X <> Y	Returns TRUE if X is not equal to Y.
BETWEEN	X [NOT] BETWEEN Y AND Z	Returns TRUE if X is [not] within the range specified. The result of X BETWEEN Y AND Z is equivalent to Y <= X AND X <= Z but X is evaluated only once in the former.
LIKE	X [NOT] LIKE Y	See the `LIKE` operator for details.
IN	Multiple	See the `IN` operator for details.

When testing values that have a struct data type for equality, it's possible that one or more fields are NULL. In such cases:

• If all non-NULL field values are equal, the comparison returns NULL.
• If any non-NULL field values are not equal, the comparison returns FALSE.

The following table demonstrates how struct data types are compared when they have fields that are NULL valued.

Struct1	Struct2	Struct1 = Struct2
STRUCT(1, NULL)	STRUCT(1, NULL)	NULL
STRUCT(1, NULL)	STRUCT(2, NULL)	FALSE
STRUCT(1,2)	STRUCT(1, NULL)	NULL

EXISTS operator

EXISTS ( subquery )

Description

Returns TRUE if the subquery produces one or more rows. Returns FALSE if the subquery produces zero rows. Never returns NULL. To learn more about how you can use a subquery with EXISTS, see EXISTS subqueries.

Examples

In this example, the EXISTS operator returns FALSE because there are no rows in Words where the direction is south:

WITH Words AS (
  SELECT 'Intend' as value, 'east' as direction UNION ALL
  SELECT 'Secure', 'north' UNION ALL
  SELECT 'Clarity', 'west'
 )
SELECT EXISTS ( SELECT value FROM Words WHERE direction = 'south' ) as result;

+--------+
| result |
+--------+
| FALSE  |
+--------+

IN operator

The IN operator supports the following syntax:

search_value [NOT] IN value_set

value_set:
  {
    (expression[, ...])
    | (subquery)
    | UNNEST(array_expression)
  }

Description

Checks for an equal value in a set of values. Semantic rules apply, but in general, IN returns TRUE if an equal value is found, FALSE if an equal value is excluded, otherwise NULL. NOT IN returns FALSE if an equal value is found, TRUE if an equal value is excluded, otherwise NULL.

• search_value: The expression that is compared to a set of values.

• value_set: One or more values to compare to a search value.

  • (expression[, ...]): A list of expressions.
  • (subquery): A subquery that returns a single column. The values in that column are the set of values. If no rows are produced, the set of values is empty.

  • UNNEST(array_expression): An UNNEST operator that returns a column of values from an array expression. This is equivalent to:

    IN (SELECT element FROM UNNEST(array_expression) AS element)
    

This operator generally supports collation, however, [NOT] IN UNNEST does not support collation.

Semantic rules

When using the IN operator, the following semantics apply in this order:

• Returns FALSE if value_set is empty.
• Returns NULL if search_value is NULL.
• Returns TRUE if value_set contains a value equal to search_value.
• Returns NULL if value_set contains a NULL.
• Returns FALSE.

When using the NOT IN operator, the following semantics apply in this order:

• Returns TRUE if value_set is empty.
• Returns NULL if search_value is NULL.
• Returns FALSE if value_set contains a value equal to search_value.
• Returns NULL if value_set contains a NULL.
• Returns TRUE.

The semantics of:

x IN (y, z, ...)

are defined as equivalent to:

(x = y) OR (x = z) OR ...

and the subquery and array forms are defined similarly.

x NOT IN ...

is equivalent to:

NOT(x IN ...)

The UNNEST form treats an array scan like UNNEST in the FROM clause:

x [NOT] IN UNNEST(<array expression>)

This form is often used with array parameters. For example:

x IN UNNEST(@array_parameter)

See the Arrays topic for more information on how to use this syntax.

IN can be used with multi-part keys by using the struct constructor syntax. For example:

(Key1, Key2) IN ( (12,34), (56,78) )
(Key1, Key2) IN ( SELECT (table.a, table.b) FROM table )

See the Struct Type topic for more information.

Return Data Type

BOOL

Examples

You can use these WITH clauses to emulate temporary tables for Words and Items in the following examples:

WITH Words AS (
  SELECT 'Intend' as value UNION ALL
  SELECT 'Secure' UNION ALL
  SELECT 'Clarity' UNION ALL
  SELECT 'Peace' UNION ALL
  SELECT 'Intend'
 )
SELECT * FROM Words;

+----------+
| value    |
+----------+
| Intend   |
| Secure   |
| Clarity  |
| Peace    |
| Intend   |
+----------+

WITH
  Items AS (
    SELECT STRUCT('blue' AS color, 'round' AS shape) AS info UNION ALL
    SELECT STRUCT('blue', 'square') UNION ALL
    SELECT STRUCT('red', 'round')
  )
SELECT * FROM Items;

+----------------------------+
| info                       |
+----------------------------+
| {blue color, round shape}  |
| {blue color, square shape} |
| {red color, round shape}   |
+----------------------------+

Example with IN and an expression:

SELECT * FROM Words WHERE value IN ('Intend', 'Secure');

+----------+
| value    |
+----------+
| Intend   |
| Secure   |
| Intend   |
+----------+

Example with NOT IN and an expression:

SELECT * FROM Words WHERE value NOT IN ('Intend');

+----------+
| value    |
+----------+
| Secure   |
| Clarity  |
| Peace    |
+----------+

Example with IN, a scalar subquery, and an expression:

SELECT * FROM Words WHERE value IN ((SELECT 'Intend'), 'Clarity');

+----------+
| value    |
+----------+
| Intend   |
| Clarity  |
| Intend   |
+----------+

Example with IN and an UNNEST operation:

SELECT * FROM Words WHERE value IN UNNEST(['Secure', 'Clarity']);

+----------+
| value    |
+----------+
| Secure   |
| Clarity  |
+----------+

Example with IN and a struct:

SELECT
  (SELECT AS STRUCT Items.info) as item
FROM
  Items
WHERE (info.shape, info.color) IN (('round', 'blue'));

+------------------------------------+
| item                               |
+------------------------------------+
| { {blue color, round shape} info } |
+------------------------------------+

IS operators

IS operators return TRUE or FALSE for the condition they are testing. They never return NULL, even for NULL inputs, unlike the IS_INF and IS_NAN functions defined in Mathematical Functions. If NOT is present, the output BOOL value is inverted.

Function Syntax	Input Data Type	Result Data Type	Description
X IS TRUE	BOOL	BOOL	Evaluates to TRUE if X evaluates to TRUE. Otherwise, evaluates to FALSE.
X IS NOT TRUE	BOOL	BOOL	Evaluates to FALSE if X evaluates to TRUE. Otherwise, evaluates to TRUE.
X IS FALSE	BOOL	BOOL	Evaluates to TRUE if X evaluates to FALSE. Otherwise, evaluates to FALSE.
X IS NOT FALSE	BOOL	BOOL	Evaluates to FALSE if X evaluates to FALSE. Otherwise, evaluates to TRUE.
X IS NULL	Any value type	BOOL	Evaluates to TRUE if X evaluates to NULL. Otherwise evaluates to FALSE.
X IS NOT NULL	Any value type	BOOL	Evaluates to FALSE if X evaluates to NULL. Otherwise evaluates to TRUE.
X IS UNKNOWN	BOOL	BOOL	Evaluates to TRUE if X evaluates to NULL. Otherwise evaluates to FALSE.
X IS NOT UNKNOWN	BOOL	BOOL	Evaluates to FALSE if X evaluates to NULL. Otherwise, evaluates to TRUE.

LIKE operator

expression_1 IS [NOT] LIKE expression_2

Description

IS LIKE returns TRUE if the string in the first operand expression_1 matches a pattern specified by the second operand expression_2, otherwise returns FALSE.

IS NOT LIKE returns TRUE if the string in the first operand expression_1 does not match a pattern specified by the second operand expression_2, otherwise returns FALSE.

Expressions can contain these characters:

• A percent sign (%) matches any number of characters or bytes.
• An underscore (_) matches a single character or byte.
• You can escape \, _, or % using two backslashes. For example, \\%. If you are using raw strings, only a single backslash is required. For example, r'\%'.

Return type

BOOL

Examples

The following examples illustrate how you can check to see if the string in the first operand matches a pattern specified by the second operand.

-- Returns TRUE
SELECT 'apple' LIKE 'a%';

-- Returns FALSE
SELECT '%a' LIKE 'apple';

-- Returns FALSE
SELECT 'apple' NOT LIKE 'a%';

-- Returns TRUE
SELECT '%a' NOT LIKE 'apple';

-- Produces an error
SELECT NULL LIKE 'a%';

-- Produces an error
SELECT 'apple' LIKE NULL;

Concatenation operator

The concatenation operator combines multiple values into one.

Function Syntax	Input Data Type	Result Data Type
STRING || STRING [ || ... ]	STRING	STRING
BYTES || BYTES [ || ... ]	BYTES	STRING
ARRAY<T> || ARRAY<T> [ || ... ]	ARRAY<T>	ARRAY<T>

Conditional expressions in GoogleSQL

GoogleSQL for Spanner supports conditional expressions. Conditional expressions impose constraints on the evaluation order of their inputs. In essence, they are evaluated left to right, with short-circuiting, and only evaluate the output value that was chosen. In contrast, all inputs to regular functions are evaluated before calling the function. Short-circuiting in conditional expressions can be exploited for error handling or performance tuning.

CASE expr

CASE expr
  WHEN expr_to_match THEN result
  [ ... ]
  [ ELSE else_result ]
  END

Description

Compares expr to expr_to_match of each successive WHEN clause and returns the first result where this comparison evaluates to TRUE. The remaining WHEN clauses and else_result aren't evaluated.

If the expr = expr_to_match comparison evaluates to FALSE or NULL for all WHEN clauses, returns the evaluation of else_result if present; if else_result isn't present, then returns NULL.

Consistent with equality comparisons elsewhere, if both expr and expr_to_match are NULL, then expr = expr_to_match evaluates to NULL, which returns else_result. If a CASE statement needs to distinguish a NULL value, then the alternate CASE syntax should be used.

expr and expr_to_match can be any type. They must be implicitly coercible to a common supertype; equality comparisons are done on coerced values. There may be multiple result types. result and else_result expressions must be coercible to a common supertype.

Return Data Type

Supertype of result[, ...] and else_result.

Example

WITH Numbers AS (
  SELECT 90 as A, 2 as B UNION ALL
  SELECT 50, 8 UNION ALL
  SELECT 60, 6 UNION ALL
  SELECT 50, 10
)
SELECT
  A,
  B,
  CASE A
    WHEN 90 THEN 'red'
    WHEN 50 THEN 'blue'
    ELSE 'green'
    END
    AS result
FROM Numbers

+------------------+
| A  | B  | result |
+------------------+
| 90 | 2  | red    |
| 50 | 8  | blue   |
| 60 | 6  | green  |
| 50 | 10 | blue   |
+------------------+

CASE

CASE
  WHEN condition THEN result
  [ ... ]
  [ ELSE else_result ]
  END

Description

Evaluates the condition of each successive WHEN clause and returns the first result where the condition evaluates to TRUE; any remaining WHEN clauses and else_result aren't evaluated.

If all conditions evaluate to FALSE or NULL, returns evaluation of else_result if present; if else_result isn't present, then returns NULL.

For additional rules on how values are evaluated, see the three-valued logic table in Logical operators.

condition must be a boolean expression. There may be multiple result types. result and else_result expressions must be implicitly coercible to a common supertype.

Return Data Type

Supertype of result[, ...] and else_result.

Example

WITH Numbers AS (
  SELECT 90 as A, 2 as B UNION ALL
  SELECT 50, 6 UNION ALL
  SELECT 20, 10
)
SELECT
  A,
  B,
  CASE
    WHEN A > 60 THEN 'red'
    WHEN B = 6 THEN 'blue'
    ELSE 'green'
    END
    AS result
FROM Numbers

+------------------+
| A  | B  | result |
+------------------+
| 90 | 2  | red    |
| 50 | 6  | blue   |
| 20 | 10 | green  |
+------------------+

COALESCE

COALESCE(expr[, ...])

Description

Returns the value of the first non-NULL expression. The remaining expressions aren't evaluated. An input expression can be any type. There may be multiple input expression types. All input expressions must be implicitly coercible to a common supertype.

Return Data Type

Supertype of expr[, ...].

Examples

SELECT COALESCE('A', 'B', 'C') as result

+--------+
| result |
+--------+
| A      |
+--------+

SELECT COALESCE(NULL, 'B', 'C') as result

+--------+
| result |
+--------+
| B      |
+--------+

IF

IF(expr, true_result, else_result)

Description

If expr evaluates to TRUE, returns true_result, else returns the evaluation for else_result. else_result isn't evaluated if expr evaluates to TRUE. true_result isn't evaluated if expr evaluates to FALSE or NULL.

expr must be a boolean expression. true_result and else_result must be coercible to a common supertype.

Return Data Type

Supertype of true_result and else_result.

Example

WITH Numbers AS (
  SELECT 10 as A, 20 as B UNION ALL
  SELECT 50, 30 UNION ALL
  SELECT 60, 60
)
SELECT
  A,
  B,
  IF(A < B, 'true', 'false') AS result
FROM Numbers

+------------------+
| A  | B  | result |
+------------------+
| 10 | 20 | true   |
| 50 | 30 | false  |
| 60 | 60 | false  |
+------------------+

IFNULL

IFNULL(expr, null_result)

Description

If expr evaluates to NULL, returns null_result. Otherwise, returns expr. If expr doesn't evaluate to NULL, null_result isn't evaluated.

expr and null_result can be any type and must be implicitly coercible to a common supertype. Synonym for COALESCE(expr, null_result).

Return Data Type

Supertype of expr or null_result.

Examples

SELECT IFNULL(NULL, 0) as result

+--------+
| result |
+--------+
| 0      |
+--------+

SELECT IFNULL(10, 0) as result

+--------+
| result |
+--------+
| 10     |
+--------+

NULLIF

NULLIF(expr, expr_to_match)

Description

Returns NULL if expr = expr_to_match evaluates to TRUE, otherwise returns expr.

expr and expr_to_match must be implicitly coercible to a common supertype, and must be comparable.

Note: NULLIF does not support STRUCT types.

Return Data Type

Supertype of expr and expr_to_match.

Example

SELECT NULLIF(0, 0) as result

+--------+
| result |
+--------+
| NULL   |
+--------+

SELECT NULLIF(10, 0) as result

+--------+
| result |
+--------+
| 10     |
+--------+

---

FUNCTIONS

Aggregate functions in GoogleSQL

GoogleSQL for Spanner supports the following general aggregate functions. To learn about the syntax for aggregate function calls, see Aggregate function calls.

ANY_VALUE

ANY_VALUE(
  expression
  [ HAVING { MAX | MIN } expression2 ]
)

Description

Returns expression for some row chosen from the group. Which row is chosen is nondeterministic, not random. Returns NULL when the input produces no rows. Returns NULL when expression is NULL for all rows in the group.

ANY_VALUE behaves as if IGNORE NULLS is specified; rows for which expression is NULL are not considered and won't be selected.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

Supported Argument Types

Any

Returned Data Types

Matches the input data type.

Examples

SELECT ANY_VALUE(fruit) as any_value
FROM UNNEST(["apple", "banana", "pear"]) as fruit;

+-----------+
| any_value |
+-----------+
| apple     |
+-----------+

WITH
  Store AS (
    SELECT 20 AS sold, "apples" AS fruit
    UNION ALL
    SELECT 30 AS sold, "pears" AS fruit
    UNION ALL
    SELECT 30 AS sold, "bananas" AS fruit
    UNION ALL
    SELECT 10 AS sold, "oranges" AS fruit
  )
SELECT ANY_VALUE(fruit HAVING MAX sold) AS a_highest_selling_fruit FROM Store;

+-------------------------+
| a_highest_selling_fruit |
+-------------------------+
| pears                   |
+-------------------------+

WITH
  Store AS (
    SELECT 20 AS sold, "apples" AS fruit
    UNION ALL
    SELECT 30 AS sold, "pears" AS fruit
    UNION ALL
    SELECT 30 AS sold, "bananas" AS fruit
    UNION ALL
    SELECT 10 AS sold, "oranges" AS fruit
  )
SELECT ANY_VALUE(fruit HAVING MIN sold) AS a_lowest_selling_fruit FROM Store;

+-------------------------+
| a_lowest_selling_fruit  |
+-------------------------+
| oranges                 |
+-------------------------+

ARRAY_AGG

ARRAY_AGG(
  [ DISTINCT ]
  expression
  [ { IGNORE | RESPECT } NULLS ]
  [ HAVING { MAX | MIN } expression2 ]
)

Description

Returns an ARRAY of expression values.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

Supported Argument Types

All data types except ARRAY.

Returned Data Types

ARRAY

If there are zero input rows, this function returns NULL.

Examples

SELECT ARRAY_AGG(x) AS array_agg FROM UNNEST([2, 1,-2, 3, -2, 1, 2]) AS x;

+-------------------------+
| array_agg               |
+-------------------------+
| [2, 1, -2, 3, -2, 1, 2] |
+-------------------------+

SELECT ARRAY_AGG(DISTINCT x) AS array_agg
FROM UNNEST([2, 1, -2, 3, -2, 1, 2]) AS x;

+---------------+
| array_agg     |
+---------------+
| [2, 1, -2, 3] |
+---------------+

SELECT ARRAY_AGG(x IGNORE NULLS) AS array_agg
FROM UNNEST([NULL, 1, -2, 3, -2, 1, NULL]) AS x;

+-------------------+
| array_agg         |
+-------------------+
| [1, -2, 3, -2, 1] |
+-------------------+

WITH vals AS
  (
    SELECT 1 x, 'a' y UNION ALL
    SELECT 1 x, 'b' y UNION ALL
    SELECT 2 x, 'a' y UNION ALL
    SELECT 2 x, 'c' y
  )
SELECT x, ARRAY_AGG(y) as array_agg
FROM vals
GROUP BY x;

+---------------+
| x | array_agg |
+---------------+
| 1 | [a, b]    |
| 2 | [a, c]    |
+---------------+

ARRAY_CONCAT_AGG

ARRAY_CONCAT_AGG(
  expression
  [ HAVING { MAX | MIN } expression2 ]
)

Description

Concatenates elements from expression of type ARRAY, returning a single array as a result.

This function ignores NULL input arrays, but respects the NULL elements in non-NULL input arrays. Returns NULL if there are zero input rows or expression evaluates to NULL for all rows.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

Supported Argument Types

ARRAY

Returned Data Types

ARRAY

Examples

SELECT ARRAY_CONCAT_AGG(x) AS array_concat_agg FROM (
  SELECT [NULL, 1, 2, 3, 4] AS x
  UNION ALL SELECT NULL
  UNION ALL SELECT [5, 6]
  UNION ALL SELECT [7, 8, 9]
);

+-----------------------------------+
| array_concat_agg                  |
+-----------------------------------+
| [NULL, 1, 2, 3, 4, 5, 6, 7, 8, 9] |
+-----------------------------------+

AVG

AVG(
  [ DISTINCT ]
  expression
  [ HAVING { MAX | MIN } expression2 ]
)

Description

Returns the average of non-NULL values in an aggregated group.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

Caveats:

• If the aggregated group is empty or the argument is NULL for all rows in the group, returns NULL.
• If the argument is NaN for any row in the group, returns NaN.
• If the argument is [+|-]Infinity for any row in the group, returns either [+|-]Infinity or NaN.
• If there is numeric overflow, produces an error.
• If a floating-point type is returned, the result is non-deterministic, which means you might receive a different result each time you use this function.

Supported Argument Types

• Any numeric input type

Returned Data Types

INPUT	INT64	NUMERIC	FLOAT64
OUTPUT	FLOAT64	NUMERIC	FLOAT64

Examples

SELECT AVG(x) as avg
FROM UNNEST([0, 2, 4, 4, 5]) as x;

+-----+
| avg |
+-----+
| 3   |
+-----+

SELECT AVG(DISTINCT x) AS avg
FROM UNNEST([0, 2, 4, 4, 5]) AS x;

+------+
| avg  |
+------+
| 2.75 |
+------+

BIT_AND

BIT_AND(
  [ DISTINCT ]
  expression
  [ HAVING { MAX | MIN } expression2 ]
)

Description

Performs a bitwise AND operation on expression and returns the result.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

Supported Argument Types

• INT64

Returned Data Types

INT64

Examples

SELECT BIT_AND(x) as bit_and FROM UNNEST([0xF001, 0x00A1]) as x;

+---------+
| bit_and |
+---------+
| 1       |
+---------+

BIT_OR

BIT_OR(
  [ DISTINCT ]
  expression
  [ HAVING { MAX | MIN } expression2 ]
)

Description

Performs a bitwise OR operation on expression and returns the result.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

Supported Argument Types

• INT64

Returned Data Types

INT64

Examples

SELECT BIT_OR(x) as bit_or FROM UNNEST([0xF001, 0x00A1]) as x;

+--------+
| bit_or |
+--------+
| 61601  |
+--------+

BIT_XOR

BIT_XOR(
  [ DISTINCT ]
  expression
  [ HAVING { MAX | MIN } expression2 ]
)

Description

Performs a bitwise XOR operation on expression and returns the result.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

Supported Argument Types

• INT64

Returned Data Types

INT64

Examples

SELECT BIT_XOR(x) AS bit_xor FROM UNNEST([5678, 1234]) AS x;

+---------+
| bit_xor |
+---------+
| 4860    |
+---------+

SELECT BIT_XOR(x) AS bit_xor FROM UNNEST([1234, 5678, 1234]) AS x;

+---------+
| bit_xor |
+---------+
| 5678    |
+---------+

SELECT BIT_XOR(DISTINCT x) AS bit_xor FROM UNNEST([1234, 5678, 1234]) AS x;

+---------+
| bit_xor |
+---------+
| 4860    |
+---------+

COUNT

1.

COUNT(*)

2.

COUNT(
  [ DISTINCT ]
  expression
  [ HAVING { MAX | MIN } expression2 ]
)

Description

1. Returns the number of rows in the input.
2. Returns the number of rows with expression evaluated to any value other than NULL.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

Supported Argument Types

expression can be any data type. If DISTINCT is present, expression can only be a data type that is groupable.

Return Data Types

INT64

Examples

You can use the COUNT function to return the number of rows in a table or the number of distinct values of an expression. For example:

SELECT
  COUNT(*) AS count_star,
  COUNT(DISTINCT x) AS count_dist_x
FROM UNNEST([1, 4, 4, 5]) AS x;

+------------+--------------+
| count_star | count_dist_x |
+------------+--------------+
| 4          | 3            |
+------------+--------------+

SELECT COUNT(*) AS count_star, COUNT(x) AS count_x
FROM UNNEST([1, 4, NULL, 4, 5]) AS x;

+------------+---------+
| count_star | count_x |
+------------+---------+
| 5          | 4       |
+------------+---------+

If you want to count the number of distinct values of an expression for which a certain condition is satisfied, this is one recipe that you can use:

COUNT(DISTINCT IF(condition, expression, NULL))

Here, IF will return the value of expression if condition is TRUE, or NULL otherwise. The surrounding COUNT(DISTINCT ...) will ignore the NULL values, so it will count only the distinct values of expression for which condition is TRUE.

For example, to count the number of distinct positive values of x:

SELECT COUNT(DISTINCT IF(x > 0, x, NULL)) AS distinct_positive
FROM UNNEST([1, -2, 4, 1, -5, 4, 1, 3, -6, 1]) AS x;

+-------------------+
| distinct_positive |
+-------------------+
| 3                 |
+-------------------+

Or to count the number of distinct dates on which a certain kind of event occurred:

WITH Events AS (
  SELECT DATE '2021-01-01' AS event_date, 'SUCCESS' AS event_type
  UNION ALL
  SELECT DATE '2021-01-02' AS event_date, 'SUCCESS' AS event_type
  UNION ALL
  SELECT DATE '2021-01-02' AS event_date, 'FAILURE' AS event_type
  UNION ALL
  SELECT DATE '2021-01-03' AS event_date, 'SUCCESS' AS event_type
  UNION ALL
  SELECT DATE '2021-01-04' AS event_date, 'FAILURE' AS event_type
  UNION ALL
  SELECT DATE '2021-01-04' AS event_date, 'FAILURE' AS event_type
)
SELECT
  COUNT(DISTINCT IF(event_type = 'FAILURE', event_date, NULL))
    AS distinct_dates_with_failures
FROM Events;

+------------------------------+
| distinct_dates_with_failures |
+------------------------------+
| 2                            |
+------------------------------+

COUNTIF

COUNTIF(
  [ DISTINCT ]
  expression
  [ HAVING { MAX | MIN } expression2 ]
)

Description

Returns the count of TRUE values for expression. Returns 0 if there are zero input rows, or if expression evaluates to FALSE or NULL for all rows.

Since expression must be a BOOL, the form COUNTIF(DISTINCT ...) is generally not useful: there is only one distinct value of TRUE. So COUNTIF(DISTINCT ...) will return 1 if expression evaluates to TRUE for one or more input rows, or 0 otherwise. Usually when someone wants to combine COUNTIF and DISTINCT, they want to count the number of distinct values of an expression for which a certain condition is satisfied. One recipe to achieve this is the following:

COUNT(DISTINCT IF(condition, expression, NULL))

Note that this uses COUNT, not COUNTIF; the IF part has been moved inside. To learn more, see the examples for COUNT.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

Supported Argument Types

BOOL

Return Data Types

INT64

Examples

SELECT COUNTIF(x<0) AS num_negative, COUNTIF(x>0) AS num_positive
FROM UNNEST([5, -2, 3, 6, -10, -7, 4, 0]) AS x;

+--------------+--------------+
| num_negative | num_positive |
+--------------+--------------+
| 3            | 4            |
+--------------+--------------+

LOGICAL_AND

LOGICAL_AND(
  expression
  [ HAVING { MAX | MIN } expression2 ]
)

Description

Returns the logical AND of all non-NULL expressions. Returns NULL if there are zero input rows or expression evaluates to NULL for all rows.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

Supported Argument Types

BOOL

Return Data Types

BOOL

Examples

LOGICAL_AND returns FALSE because not all of the values in the array are less than 3.

SELECT LOGICAL_AND(x < 3) AS logical_and FROM UNNEST([1, 2, 4]) AS x;

+-------------+
| logical_and |
+-------------+
| FALSE       |
+-------------+

LOGICAL_OR

LOGICAL_OR(
  expression
  [ HAVING { MAX | MIN } expression2 ]
)

Description

Returns the logical OR of all non-NULL expressions. Returns NULL if there are zero input rows or expression evaluates to NULL for all rows.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

Supported Argument Types

BOOL

Return Data Types

BOOL

Examples

LOGICAL_OR returns TRUE because at least one of the values in the array is less than 3.

SELECT LOGICAL_OR(x < 3) AS logical_or FROM UNNEST([1, 2, 4]) AS x;

+------------+
| logical_or |
+------------+
| TRUE       |
+------------+

MAX

MAX(
  expression
  [ HAVING { MAX | MIN } expression2 ]
)

Description

Returns the maximum non-NULL value in an aggregated group.

Caveats:

• If the aggregated group is empty or the argument is NULL for all rows in the group, returns NULL.
• If the argument is NaN for any row in the group, returns NaN.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

Supported Argument Types

Any orderable data type except for ARRAY.

Return Data Types

The data type of the input values.

Examples

SELECT MAX(x) AS max
FROM UNNEST([8, 37, 55, 4]) AS x;

+-----+
| max |
+-----+
| 55  |
+-----+

MIN

MIN(
  expression
  [ HAVING { MAX | MIN } expression2 ]
)

Description

Returns the minimum non-NULL value in an aggregated group.

Caveats:

• If the aggregated group is empty or the argument is NULL for all rows in the group, returns NULL.
• If the argument is NaN for any row in the group, returns NaN.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

Supported Argument Types

Any orderable data type except for ARRAY.

Return Data Types

The data type of the input values.

Examples

SELECT MIN(x) AS min
FROM UNNEST([8, 37, 4, 55]) AS x;

+-----+
| min |
+-----+
| 4   |
+-----+

STRING_AGG

STRING_AGG(
  [ DISTINCT ]
  expression [, delimiter]
  [ HAVING { MAX | MIN } expression2 ]
)

Description

Returns a value (either STRING or BYTES) obtained by concatenating non-NULL values. Returns NULL if there are zero input rows or expression evaluates to NULL for all rows.

If a delimiter is specified, concatenated values are separated by that delimiter; otherwise, a comma is used as a delimiter.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

Supported Argument Types

Either STRING or BYTES.

Return Data Types

Either STRING or BYTES.

Examples

SELECT STRING_AGG(fruit) AS string_agg
FROM UNNEST(["apple", NULL, "pear", "banana", "pear"]) AS fruit;

+------------------------+
| string_agg             |
+------------------------+
| apple,pear,banana,pear |
+------------------------+

SELECT STRING_AGG(fruit, " & ") AS string_agg
FROM UNNEST(["apple", "pear", "banana", "pear"]) AS fruit;

+------------------------------+
| string_agg                   |
+------------------------------+
| apple & pear & banana & pear |
+------------------------------+

SELECT STRING_AGG(DISTINCT fruit, " & ") AS string_agg
FROM UNNEST(["apple", "pear", "banana", "pear"]) AS fruit;

+-----------------------+
| string_agg            |
+-----------------------+
| apple & pear & banana |
+-----------------------+

SUM

SUM(
  [ DISTINCT ]
  expression
  [ HAVING { MAX | MIN } expression2 ]
)

Description

Returns the sum of non-NULL values in an aggregated group.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

Caveats:

• If the aggregated group is empty or the argument is NULL for all rows in the group, returns NULL.
• If the argument is NaN for any row in the group, returns NaN.
• If the argument is [+|-]Infinity for any row in the group, returns either [+|-]Infinity or NaN.
• If there is numeric overflow, produces an error.
• If a floating-point type is returned, the result is non-deterministic, which means you might receive a different result each time you use this function.

Supported Argument Types

• Any supported numeric data type

Return Data Types

INPUT	INT64	NUMERIC	FLOAT64
OUTPUT	INT64	NUMERIC	FLOAT64

Examples

SELECT SUM(x) AS sum
FROM UNNEST([1, 2, 3, 4, 5, 4, 3, 2, 1]) AS x;

+-----+
| sum |
+-----+
| 25  |
+-----+

SELECT SUM(DISTINCT x) AS sum
FROM UNNEST([1, 2, 3, 4, 5, 4, 3, 2, 1]) AS x;

+-----+
| sum |
+-----+
| 15  |
+-----+

SELECT SUM(x) AS sum
FROM UNNEST([]) AS x;

+------+
| sum  |
+------+
| NULL |
+------+

Statistical aggregate functions in GoogleSQL

GoogleSQL for Spanner supports statistical aggregate functions. To learn about the syntax for aggregate function calls, see Aggregate function calls.

STDDEV_SAMP

STDDEV_SAMP(
  [ DISTINCT ]
  expression
  [ HAVING { MAX | MIN } expression2 ]
)

Description

Returns the sample (unbiased) standard deviation of the values. The return result is between 0 and +Inf.

All numeric types are supported. If the input is NUMERIC then the internal aggregation is stable with the final output converted to a FLOAT64. Otherwise the input is converted to a FLOAT64 before aggregation, resulting in a potentially unstable result.

This function ignores any NULL inputs. If there are fewer than two non-NULL inputs, this function returns NULL.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

Return Data Type

FLOAT64

STDDEV

STDDEV(
  [ DISTINCT ]
  expression
  [ HAVING { MAX | MIN } expression2 ]
)

Description

An alias of STDDEV_SAMP.

VAR_SAMP

VAR_SAMP(
  [ DISTINCT ]
  expression
  [ HAVING { MAX | MIN } expression2 ]
)

Description

Returns the sample (unbiased) variance of the values. The return result is between 0 and +Inf.

All numeric types are supported. If the input is NUMERIC then the internal aggregation is stable with the final output converted to a FLOAT64. Otherwise the input is converted to a FLOAT64 before aggregation, resulting in a potentially unstable result.

This function ignores any NULL inputs. If there are fewer than two non-NULL inputs, this function returns NULL.

To learn more about the optional arguments in this function and how to use them, see Aggregate function calls.

Return Data Type

FLOAT64

VARIANCE

VARIANCE(
  [ DISTINCT ]
  expression
  [ HAVING { MAX | MIN } expression2 ]
)

Description

An alias of VAR_SAMP.

Conversion functions in GoogleSQL

GoogleSQL for Spanner supports conversion functions. These data type conversions are explicit, but some conversions can happen implicitly. You can learn more about implicit and explicit conversion here.

CAST

CAST(expression AS typename)

Description

Cast syntax is used in a query to indicate that the result type of an expression should be converted to some other type.

When using CAST, a query can fail if GoogleSQL is unable to perform the cast. If you want to protect your queries from these types of errors, you can use SAFE_CAST.

Casts between supported types that do not successfully map from the original value to the target domain produce runtime errors. For example, casting BYTES to STRING where the byte sequence is not valid UTF-8 results in a runtime error.

Examples

The following query results in "true" if x is 1, "false" for any other non-NULL value, and NULL if x is NULL.

CAST(x=1 AS STRING)

CAST AS ARRAY

CAST(expression AS ARRAY<element_type>)

Description

GoogleSQL supports casting to ARRAY. The expression parameter can represent an expression for these data types:

• ARRAY

Conversion rules

From	To	Rule(s) when casting x
ARRAY	ARRAY	Must be the exact same array type.

CAST AS BOOL

CAST(expression AS BOOL)

Description

GoogleSQL supports casting to BOOL. The expression parameter can represent an expression for these data types:

• INT64
• BOOL
• STRING

Conversion rules

From	To	Rule(s) when casting x
INT64	BOOL	Returns FALSE if x is 0, TRUE otherwise.
STRING	BOOL	Returns TRUE if x is "true" and FALSE if x is "false" All other values of x are invalid and throw an error instead of casting to a boolean. A string is case-insensitive when converting to a boolean.

CAST AS BYTES

CAST(expression AS BYTES)

Description

GoogleSQL supports casting to BYTES. The expression parameter can represent an expression for these data types:

• BYTES
• STRING

Conversion rules

From	To	Rule(s) when casting x
STRING	BYTES	Strings are cast to bytes using UTF-8 encoding. For example, the string "©", when cast to bytes, would become a 2-byte sequence with the hex values C2 and A9.

CAST AS DATE

CAST(expression AS DATE)

Description

GoogleSQL supports casting to DATE. The expression parameter can represent an expression for these data types:

• STRING
• TIMESTAMP

Conversion rules

From	To	Rule(s) when casting x
STRING	DATE	When casting from string to date, the string must conform to the supported date literal format, and is independent of time zone. If the string expression is invalid or represents a date that is outside of the supported min/max range, then an error is produced.
TIMESTAMP	DATE	Casting from a timestamp to date effectively truncates the timestamp as of the default time zone.

CAST AS FLOAT64

CAST(expression AS FLOAT64)

Description

GoogleSQL supports casting to floating point types. The expression parameter can represent an expression for these data types:

• INT64
• FLOAT64
• NUMERIC
• STRING

Conversion rules

From	To	Rule(s) when casting x
INT64	FLOAT64	Returns a close but potentially not exact floating point value.
NUMERIC	FLOAT64	NUMERIC will convert to the closest floating point number with a possible loss of precision.
STRING	FLOAT64	Returns x as a floating point value, interpreting it as having the same form as a valid floating point literal. Also supports casts from "[+,-]inf" to [,-]Infinity, "[+,-]infinity" to [,-]Infinity, and "[+,-]nan" to NaN. Conversions are case-insensitive.

CAST AS INT64

CAST(expression AS INT64)

Description

GoogleSQL supports casting to integer types. The expression parameter can represent an expression for these data types:

• INT64
• FLOAT64
• NUMERIC
• BOOL
• STRING

Conversion rules

From	To	Rule(s) when casting x
FLOAT64	INT64	Returns the closest integer value. Halfway cases such as 1.5 or -0.5 round away from zero.
BOOL	INT64	Returns 1 if x is TRUE, 0 otherwise.
STRING	INT64	A hex string can be cast to an integer. For example, 0x123 to 291 or -0x123 to -291.

Examples

If you are working with hex strings (0x123), you can cast those strings as integers:

SELECT '0x123' as hex_value, CAST('0x123' as INT64) as hex_to_int;

+-----------+------------+
| hex_value | hex_to_int |
+-----------+------------+
| 0x123     | 291        |
+-----------+------------+

SELECT '-0x123' as hex_value, CAST('-0x123' as INT64) as hex_to_int;

+-----------+------------+
| hex_value | hex_to_int |
+-----------+------------+
| -0x123    | -291       |
+-----------+------------+

CAST AS NUMERIC

CAST(expression AS NUMERIC)

Description

GoogleSQL supports casting to NUMERIC. The expression parameter can represent an expression for these data types:

• INT64
• FLOAT64
• NUMERIC
• STRING

Conversion rules

From	To	Rule(s) when casting x
FLOAT64	NUMERIC	The floating point number will round half away from zero. Casting a NaN, +inf or -inf will return an error. Casting a value outside the range of NUMERIC returns an overflow error.
STRING	NUMERIC	The numeric literal contained in the string must not exceed the maximum precision or range of the NUMERIC type, or an error will occur. If the number of digits after the decimal point exceeds nine, then the resulting NUMERIC value will round half away from zero. to have nine digits after the decimal point.

CAST AS STRING

CAST(expression AS STRING)

Description

GoogleSQL supports casting to STRING. The expression parameter can represent an expression for these data types:

• INT64
• FLOAT64
• NUMERIC
• BOOL
• BYTES
• DATE
• TIMESTAMP
• STRING

Conversion rules

From	To	Rule(s) when casting x
FLOAT64	STRING	Returns an approximate string representation. A returned NaN or 0 will not be signed.
BOOL	STRING	Returns "true" if x is TRUE, "false" otherwise.
BYTES	STRING	Returns x interpreted as a UTF-8 string. For example, the bytes literal b'\xc2\xa9', when cast to a string, is interpreted as UTF-8 and becomes the unicode character "©". An error occurs if x is not valid UTF-8.
DATE	STRING	Casting from a date type to a string is independent of time zone and is of the form YYYY-MM-DD.
TIMESTAMP	STRING	When casting from timestamp types to string, the timestamp is interpreted using the default time zone, America/Los_Angeles. The number of subsecond digits produced depends on the number of trailing zeroes in the subsecond part: the CAST function will truncate zero, three, or six digits.

Examples

SELECT CAST(CURRENT_DATE() AS STRING) AS current_date

+---------------+
| current_date  |
+---------------+
| 2021-03-09    |
+---------------+

CAST AS STRUCT

CAST(expression AS STRUCT)

Description

GoogleSQL supports casting to STRUCT. The expression parameter can represent an expression for these data types:

• STRUCT

Conversion rules

From	To	Rule(s) when casting x
STRUCT	STRUCT	Allowed if the following conditions are met: The two structs have the same number of fields. The original struct field types can be explicitly cast to the corresponding target struct field types (as defined by field order, not field name).

CAST AS TIMESTAMP

CAST(expression AS TIMESTAMP)

Description

GoogleSQL supports casting to TIMESTAMP. The expression parameter can represent an expression for these data types:

• STRING
• TIMESTAMP

Conversion rules

From	To	Rule(s) when casting x
STRING	TIMESTAMP	When casting from string to a timestamp, string_expression must conform to the supported timestamp literal formats, or else a runtime error occurs. The string_expression may itself contain a time zone. If there is a time zone in the string_expression, that time zone is used for conversion, otherwise the default time zone, America/Los_Angeles, is used. If the string has fewer than six digits, then it is implicitly widened. An error is produced if the string_expression is invalid, has more than six subsecond digits (i.e. precision greater than microseconds), or represents a time outside of the supported timestamp range.
DATE	TIMESTAMP	Casting from a date to a timestamp interprets date_expression as of midnight (start of the day) in the default time zone, America/Los_Angeles.

Examples

The following example casts a string-formatted timestamp as a timestamp:

SELECT CAST("2020-06-02 17:00:53.110+00:00" AS TIMESTAMP) AS as_timestamp

-- Results depend upon where this query was executed.
+-------------------------+
| as_timestamp            |
+-------------------------+
| 2020-06-03T00:00:53.11Z |
+-------------------------+

SAFE_CAST

SAFE_CAST(expression AS typename)

Description

When using CAST, a query can fail if GoogleSQL is unable to perform the cast. For example, the following query generates an error:

SELECT CAST("apple" AS INT64) AS not_a_number;

If you want to protect your queries from these types of errors, you can use SAFE_CAST. SAFE_CAST is identical to CAST, except it returns NULL instead of raising an error.

SELECT SAFE_CAST("apple" AS INT64) AS not_a_number;

+--------------+
| not_a_number |
+--------------+
| NULL         |
+--------------+

If you are casting from bytes to strings, you can also use the function, SAFE_CONVERT_BYTES_TO_STRING. Any invalid UTF-8 characters are replaced with the unicode replacement character, U+FFFD.

Other conversion functions

You can learn more about these conversion functions elsewhere in the documentation:

Conversion function	From	To
ARRAY_TO_STRING	ARRAY	STRING
DATE	Various data types	DATE
FROM_BASE32	STRING	BYTEs
FROM_BASE64	STRING	BYTES
FROM_HEX	STRING	BYTES
PARSE_DATE	STRING	DATE
PARSE_JSON	STRING	JSON
PARSE_TIMESTAMP	STRING	TIMESTAMP
SAFE_CONVERT_BYTES_TO_STRING	BYTES	STRING
STRING	TIMESTAMP	STRING
TIMESTAMP	Various data types	TIMESTAMP
TO_BASE32	BYTES	STRING
TO_BASE64	BYTES	STRING
TO_HEX	BYTES	STRING
TO_JSON	All data types	JSON
TO_JSON_STRING	JSON	STRING

Machine learning functions in GoogleSQL

GoogleSQL for Spanner supports the following machine learning (ML) functions.

ML.PREDICT

ML.PREDICT(input_model, input_relation)

input_model:
  MODEL model_name

input_relation:
  { input_table | input_subquery }

input_table:
  TABLE table_name

Description

ML.PREDICT is a table-valued function that helps to access registered machine learning (ML) models and use them to generate ML predictions. This function applies ML computations defined by a model to each row of an input relation, and then, it returns the results of the predictions.

Note: Make sure that Spanner has access to the referenced Vertex AI endpoint as described in Model endpoint access control.

Supported Argument Types

• input_model: The model to use for predictions. Replace model_name with the name of the model. To create a model, see CREATE_MODEL.
• input_relation: A table or subquery upon which to apply ML computations. The set of columns of the input relation must include all input columns of the input model; otherwise, the input won't have enough data to generate predictions and the query won't compile. Additionally, the set can also include arbitrary pass-through columns that will be included in the output. The order of the columns in the input relation doesn't matter. The columns of the input relation and model must be coercible.
• input_table: The table containing the input data for predictions, for example, a set of features. Replace table_name with the name of the table.
• input_subquery: The subquery that's used to generate the prediction input data.

Return Type

A table with the following columns:

• Model outputs
• Pass-through columns from the input relation

Note: If a column of the input relation has the same name as one of the output columns, the value of the output column is returned.

Examples

The examples in this section reference a model called DiamondAppraise and an input table called Diamonds with the following columns:

• DiamondAppraise model:

  Input columns	Output columns
  value FLOAT64	value FLOAT64
  carat FLOAT64	lower_bound FLOAT64
  cut STRING	upper_bound FLOAT64
  color STRING(1)

• Diamonds table:

  Columns
  Id INT64
  Carat FLOAT64
  Cut STRING
  Color STRING

The following query predicts the value of a diamond based on the diamond's carat, cut, and color.

SELECT id, color, value
FROM ML.PREDICT(MODEL DiamondAppraise, TABLE Diamonds);

+----+-------+-------+
| id | color | value |
+----+-------+-------+
| 1  | I     | 280   |
| 2  | G     | 447   |
+----+-------+-------+

You can use ML.PREDICT in any DQL/DML statements, such as INSERT or UPDATE. For example:

INSERT INTO AppraisedDiamond (id, color, carat, value)
SELECT
  1 AS id,
  color,
  carat,
  value
FROM
  ML.PREDICT(MODEL DiamondAppraise,
  (
    SELECT
      @carat AS carat,
      @cut AS cut,
      @color AS color
  ));

Mathematical functions in GoogleSQL

GoogleSQL for Spanner supports mathematical functions. All mathematical functions have the following behaviors:

• They return NULL if any of the input parameters is NULL.
• They return NaN if any of the arguments is NaN.

ABS

ABS(X)

Description

Computes absolute value. Returns an error if the argument is an integer and the output value cannot be represented as the same type; this happens only for the largest negative input value, which has no positive representation.

X	ABS(X)
25	25
-25	25
+inf	+inf
-inf	+inf

Return Data Type

INPUT	INT64	NUMERIC	FLOAT64
OUTPUT	INT64	NUMERIC	FLOAT64

ACOS

ACOS(X)

Description

Computes the principal value of the inverse cosine of X. The return value is in the range [0,π]. Generates an error if X is a value outside of the range [-1, 1].

If X is NUMERIC then, the output is FLOAT64.

X	ACOS(X)
+inf	NaN
-inf	NaN
NaN	NaN
X < -1	Error
X > 1	Error

ACOSH

ACOSH(X)

Description

Computes the inverse hyperbolic cosine of X. Generates an error if X is a value less than 1.

If X is NUMERIC then, the output is FLOAT64.

X	ACOSH(X)
+inf	+inf
-inf	NaN
NaN	NaN
X < 1	Error

ASIN

ASIN(X)

Description

Computes the principal value of the inverse sine of X. The return value is in the range [-π/2,π/2]. Generates an error if X is outside of the range [-1, 1].

If X is NUMERIC then, the output is FLOAT64.

X	ASIN(X)
+inf	NaN
-inf	NaN
NaN	NaN
X < -1	Error
X > 1	Error

ASINH

ASINH(X)

Description

Computes the inverse hyperbolic sine of X. Does not fail.

If X is NUMERIC then, the output is FLOAT64.

X	ASINH(X)
+inf	+inf
-inf	-inf
NaN	NaN

ATAN

ATAN(X)

Description

Computes the principal value of the inverse tangent of X. The return value is in the range [-π/2,π/2]. Does not fail.

If X is NUMERIC then, the output is FLOAT64.

X	ATAN(X)
+inf	π/2
-inf	-π/2
NaN	NaN

ATAN2

ATAN2(X, Y)

Description

Calculates the principal value of the inverse tangent of X/Y using the signs of the two arguments to determine the quadrant. The return value is in the range [-π,π].

If Y is NUMERIC then, the output is FLOAT64.

X	Y	ATAN2(X, Y)
NaN	Any value	NaN
Any value	NaN	NaN
0.0	0.0	0.0
Positive Finite value	-inf	π
Negative Finite value	-inf	-π
Finite value	+inf	0.0
+inf	Finite value	π/2
-inf	Finite value	-π/2
+inf	-inf	¾π
-inf	-inf	-¾π
+inf	+inf	π/4
-inf	+inf	-π/4

ATANH

ATANH(X)

Description

Computes the inverse hyperbolic tangent of X. Generates an error if X is outside of the range (-1, 1).

If X is NUMERIC then, the output is FLOAT64.

X	ATANH(X)
+inf	NaN
-inf	NaN
NaN	NaN
X < -1	Error
X > 1	Error

CEIL

CEIL(X)

Description

Returns the smallest integral value that is not less than X.

X	CEIL(X)
2.0	2.0
2.3	3.0
2.8	3.0
2.5	3.0
-2.3	-2.0
-2.8	-2.0
-2.5	-2.0
0	0
+inf	+inf
-inf	-inf
NaN	NaN

Return Data Type

INPUT	INT64	NUMERIC	FLOAT64
OUTPUT	FLOAT64	NUMERIC	FLOAT64

CEILING

CEILING(X)

Description

Synonym of CEIL(X)

COS

COS(X)

Description

Computes the cosine of X where X is specified in radians. Never fails.

X	COS(X)
+inf	NaN
-inf	NaN
NaN	NaN

COSH

COSH(X)

Description

Computes the hyperbolic cosine of X where X is specified in radians. Generates an error if overflow occurs.

If X is NUMERIC then, the output is FLOAT64.

X	COSH(X)
+inf	+inf
-inf	+inf
NaN	NaN

DIV

DIV(X, Y)

Description

Returns the result of integer division of X by Y. Division by zero returns an error. Division by -1 may overflow. If both inputs are NUMERIC and the result is overflow, then it returns a numeric overflow error.

X	Y	DIV(X, Y)
20	4	5
12	-7	-1
20	3	6
0	20	0
20	0	Error

Return Data Type

The return data type is determined by the argument types with the following table.

INPUT	INT64	NUMERIC
INT64	INT64	NUMERIC
NUMERIC	NUMERIC	NUMERIC

EXP

EXP(X)

Description

Computes e to the power of X, also called the natural exponential function. If the result underflows, this function returns a zero. Generates an error if the result overflows.

X	EXP(X)
0.0	1.0
+inf	+inf
-inf	0.0

Return Data Type

INPUT	INT64	NUMERIC	FLOAT64
OUTPUT	FLOAT64	NUMERIC	FLOAT64

FLOOR

FLOOR(X)

Description

Returns the largest integral value that is not greater than X.

X	FLOOR(X)
2.0	2.0
2.3	2.0
2.8	2.0
2.5	2.0
-2.3	-3.0
-2.8	-3.0
-2.5	-3.0
0	0
+inf	+inf
-inf	-inf
NaN	NaN

Return Data Type

INPUT	INT64	NUMERIC	FLOAT64
OUTPUT	FLOAT64	NUMERIC	FLOAT64

GREATEST

GREATEST(X1,...,XN)

Description

Returns the greatest value among X1,...,XN. If any argument is NULL, returns NULL. Otherwise, in the case of floating-point arguments, if any argument is NaN, returns NaN. In all other cases, returns the value among X1,...,XN that has the greatest value according to the ordering used by the ORDER BY clause. The arguments X1, ..., XN must be coercible to a common supertype, and the supertype must support ordering.

X1,...,XN	GREATEST(X1,...,XN)
3,5,1	5

Return Data Types

Data type of the input values.

IEEE_DIVIDE

IEEE_DIVIDE(X, Y)

Description

Divides X by Y; this function never fails. Returns FLOAT64. Unlike the division operator (/), this function does not generate errors for division by zero or overflow.

X	Y	IEEE_DIVIDE(X, Y)
20.0	4.0	5.0
0.0	25.0	0.0
25.0	0.0	+inf
-25.0	0.0	-inf
0.0	0.0	NaN
0.0	NaN	NaN
NaN	0.0	NaN
+inf	+inf	NaN
-inf	-inf	NaN

IS_INF

IS_INF(X)

Description

Returns TRUE if the value is positive or negative infinity.

Returns FALSE for NUMERIC inputs since NUMERIC cannot be INF.

X	IS_INF(X)
+inf	TRUE
-inf	TRUE
25	FALSE

IS_NAN

IS_NAN(X)

Description

Returns TRUE if the value is a NaN value.

Returns FALSE for NUMERIC inputs since NUMERIC cannot be NaN.

X	IS_NAN(X)
NaN	TRUE
25	FALSE

LEAST

LEAST(X1,...,XN)

Description

Returns the least value among X1,...,XN. If any argument is NULL, returns NULL. Otherwise, in the case of floating-point arguments, if any argument is NaN, returns NaN. In all other cases, returns the value among X1,...,XN that has the least value according to the ordering used by the ORDER BY clause. The arguments X1, ..., XN must be coercible to a common supertype, and the supertype must support ordering.

X1,...,XN	LEAST(X1,...,XN)
3,5,1	1

Return Data Types

Data type of the input values.

LN

LN(X)

Description

Computes the natural logarithm of X. Generates an error if X is less than or equal to zero.

X	LN(X)
1.0	0.0
+inf	+inf
X < 0	Error

Return Data Type

INPUT	INT64	NUMERIC	FLOAT64
OUTPUT	FLOAT64	NUMERIC	FLOAT64

LOG

LOG(X [, Y])

Description

If only X is present, LOG is a synonym of LN. If Y is also present, LOG computes the logarithm of X to base Y.

X	Y	LOG(X, Y)
100.0	10.0	2.0
-inf	Any value	NaN
Any value	+inf	NaN
+inf	0.0 < Y < 1.0	-inf
+inf	Y > 1.0	+inf
X <= 0	Any value	Error
Any value	Y <= 0	Error
Any value	1.0	Error

Return Data Type

INPUT	INT64	NUMERIC	FLOAT64
INT64	FLOAT64	NUMERIC	FLOAT64
NUMERIC	NUMERIC	NUMERIC	FLOAT64
FLOAT64	FLOAT64	FLOAT64	FLOAT64

LOG10

LOG10(X)

Description

Similar to LOG, but computes logarithm to base 10.

X	LOG10(X)
100.0	2.0
-inf	NaN
+inf	+inf
X <= 0	Error

Return Data Type

INPUT	INT64	NUMERIC	FLOAT64
OUTPUT	FLOAT64	NUMERIC	FLOAT64

MOD

MOD(X, Y)

Description

Modulo function: returns the remainder of the division of X by Y. Returned value has the same sign as X. An error is generated if Y is 0.

X	Y	MOD(X, Y)
25	12	1
25	0	Error

Return Data Type

The return data type is determined by the argument types with the following table.

INPUT	INT64	NUMERIC
INT64	INT64	NUMERIC
NUMERIC	NUMERIC	NUMERIC

POW

POW(X, Y)

Description

Returns the value of X raised to the power of Y. If the result underflows and is not representable, then the function returns a value of zero.

X	Y	POW(X, Y)
2.0	3.0	8.0
1.0	Any value including NaN	1.0
Any value including NaN	0	1.0
-1.0	+inf	1.0
-1.0	-inf	1.0
ABS(X) < 1	-inf	+inf
ABS(X) > 1	-inf	0.0
ABS(X) < 1	+inf	0.0
ABS(X) > 1	+inf	+inf
-inf	Y < 0	0.0
-inf	Y > 0	-inf if Y is an odd integer, +inf otherwise
+inf	Y < 0	0
+inf	Y > 0	+inf
Finite value < 0	Non-integer	Error
0	Finite value < 0	Error

Return Data Type

The return data type is determined by the argument types with the following table.

INPUT	INT64	NUMERIC	FLOAT64
INT64	FLOAT64	NUMERIC	FLOAT64
NUMERIC	NUMERIC	NUMERIC	FLOAT64
FLOAT64	FLOAT64	FLOAT64	FLOAT64

POWER

POWER(X, Y)

Description

Synonym of POW(X, Y).

ROUND

ROUND(X [, N])

Description

If only X is present, rounds X to the nearest integer. If N is present, rounds X to N decimal places after the decimal point. If N is negative, rounds off digits to the left of the decimal point. Rounds halfway cases away from zero. Generates an error if overflow occurs.

Expression	Return Value
ROUND(2.0)	2.0
ROUND(2.3)	2.0
ROUND(2.8)	3.0
ROUND(2.5)	3.0
ROUND(-2.3)	-2.0
ROUND(-2.8)	-3.0
ROUND(-2.5)	-3.0
ROUND(0)	0
ROUND(+inf)	+inf
ROUND(-inf)	-inf
ROUND(NaN)	NaN
ROUND(123.7, -1)	120.0
ROUND(1.235, 2)	1.24

Return Data Type

INPUT	INT64	NUMERIC	FLOAT64
OUTPUT	FLOAT64	NUMERIC	FLOAT64

SAFE_ADD

SAFE_ADD(X, Y)

Description

Equivalent to the addition operator (+), but returns NULL if overflow occurs.

X	Y	SAFE_ADD(X, Y)
5	4	9

Return Data Type

INPUT	INT64	NUMERIC	FLOAT64
INT64	INT64	NUMERIC	FLOAT64
NUMERIC	NUMERIC	NUMERIC	FLOAT64
FLOAT64	FLOAT64	FLOAT64	FLOAT64

SAFE_DIVIDE

SAFE_DIVIDE(X, Y)

Description

Equivalent to the division operator (X / Y), but returns NULL if an error occurs, such as a division by zero error.

X	Y	SAFE_DIVIDE(X, Y)
20	4	5
0	20	0
20	0	NULL

Return Data Type

INPUT	INT64	NUMERIC	FLOAT64
INT64	FLOAT64	NUMERIC	FLOAT64
NUMERIC	NUMERIC	NUMERIC	FLOAT64
FLOAT64	FLOAT64	FLOAT64	FLOAT64

SAFE_MULTIPLY

SAFE_MULTIPLY(X, Y)

Description

Equivalent to the multiplication operator (*), but returns NULL if overflow occurs.

X	Y	SAFE_MULTIPLY(X, Y)
20	4	80

Return Data Type

INPUT	INT64	NUMERIC	FLOAT64
INT64	INT64	NUMERIC	FLOAT64
NUMERIC	NUMERIC	NUMERIC	FLOAT64
FLOAT64	FLOAT64	FLOAT64	FLOAT64

SAFE_NEGATE

SAFE_NEGATE(X)

Description

Equivalent to the unary minus operator (-), but returns NULL if overflow occurs.

X	SAFE_NEGATE(X)
+1	-1
-1	+1
0	0

Return Data Type

INPUT	INT64	NUMERIC	FLOAT64
OUTPUT	INT64	NUMERIC	FLOAT64

SAFE_SUBTRACT

SAFE_SUBTRACT(X, Y)

Description

Returns the result of Y subtracted from X. Equivalent to the subtraction operator (-), but returns NULL if overflow occurs.

X	Y	SAFE_SUBTRACT(X, Y)
5	4	1

Return Data Type

INPUT	INT64	NUMERIC	FLOAT64
INT64	INT64	NUMERIC	FLOAT64
NUMERIC	NUMERIC	NUMERIC	FLOAT64
FLOAT64	FLOAT64	FLOAT64	FLOAT64

SIGN

SIGN(X)

Description

Returns -1, 0, or +1 for negative, zero and positive arguments respectively. For floating point arguments, this function does not distinguish between positive and negative zero.

X	SIGN(X)
25	+1
0	0
-25	-1
NaN	NaN

Return Data Type

INPUT	INT64	NUMERIC	FLOAT64
OUTPUT	INT64	NUMERIC	FLOAT64

SIN

SIN(X)

Description

Computes the sine of X where X is specified in radians. Never fails.

X	SIN(X)
+inf	NaN
-inf	NaN
NaN	NaN

SINH

SINH(X)

Description

Computes the hyperbolic sine of X where X is specified in radians. Generates an error if overflow occurs.

If X is NUMERIC then, the output is FLOAT64.

X	SINH(X)
+inf	+inf
-inf	-inf
NaN	NaN

SQRT

SQRT(X)

Description

Computes the square root of X. Generates an error if X is less than 0.

X	SQRT(X)
25.0	5.0
+inf	+inf
X < 0	Error

Return Data Type

INPUT	INT64	NUMERIC	FLOAT64
OUTPUT	FLOAT64	NUMERIC	FLOAT64

TAN

TAN(X)

Description

Computes the tangent of X where X is specified in radians. Generates an error if overflow occurs.

X	TAN(X)
+inf	NaN
-inf	NaN
NaN	NaN

TANH

TANH(X)

Description

Computes the hyperbolic tangent of X where X is specified in radians. Does not fail.

If X is NUMERIC then, the output is FLOAT64.

X	TANH(X)
+inf	1.0
-inf	-1.0
NaN	NaN

TRUNC

TRUNC(X [, N])

Description

If only X is present, TRUNC rounds X to the nearest integer whose absolute value is not greater than the absolute value of X. If N is also present, TRUNC behaves like ROUND(X, N), but always rounds towards zero and never overflows.

X	TRUNC(X)
2.0	2.0
2.3	2.0
2.8	2.0
2.5	2.0
-2.3	-2.0
-2.8	-2.0
-2.5	-2.0
0	0
+inf	+inf
-inf	-inf
NaN	NaN

Return Data Type

INPUT	INT64	NUMERIC	FLOAT64
OUTPUT	FLOAT64	NUMERIC	FLOAT64

Hash functions in GoogleSQL

GoogleSQL for Spanner supports the following hash functions.

FARM_FINGERPRINT

FARM_FINGERPRINT(value)

Description

Computes the fingerprint of the STRING or BYTES input using the Fingerprint64 function from the open-source FarmHash library. The output of this function for a particular input will never change.

Return type

INT64

Examples

WITH example AS (
  SELECT 1 AS x, "foo" AS y, true AS z UNION ALL
  SELECT 2 AS x, "apple" AS y, false AS z UNION ALL
  SELECT 3 AS x, "" AS y, true AS z
)
SELECT
  *,
  FARM_FINGERPRINT(CONCAT(CAST(x AS STRING), y, CAST(z AS STRING)))
    AS row_fingerprint
FROM example;
+---+-------+-------+----------------------+
| x | y     | z     | row_fingerprint      |
+---+-------+-------+----------------------+
| 1 | foo   | true  | -1541654101129638711 |
| 2 | apple | false | 2794438866806483259  |
| 3 |       | true  | -4880158226897771312 |
+---+-------+-------+----------------------+

SHA1

SHA1(input)

Description

Computes the hash of the input using the SHA-1 algorithm. The input can either be STRING or BYTES. The string version treats the input as an array of bytes.

This function returns 20 bytes.

Return type

BYTES

Example

SELECT SHA1("Hello World") as sha1;

-- Note that the result of SHA1 is of type BYTES, displayed as a base64-encoded string.
+------------------------------+
| sha1                         |
+------------------------------+
| Ck1VqNd45QIvq3AZd8XYQLvEhtA= |
+------------------------------+

SHA256

SHA256(input)

Description

Computes the hash of the input using the SHA-256 algorithm. The input can either be STRING or BYTES. The string version treats the input as an array of bytes.

This function returns 32 bytes.

Return type

BYTES

Example

SELECT SHA256("Hello World") as sha256;

SHA512

SHA512(input)

Description

Computes the hash of the input using the SHA-512 algorithm. The input can either be STRING or BYTES. The string version treats the input as an array of bytes.

This function returns 64 bytes.

Return type

BYTES

Example

SELECT SHA512("Hello World") as sha512;

String functions in GoogleSQL

GoogleSQL for Spanner supports string functions. These string functions work on two different values: STRING and BYTES data types. STRING values must be well-formed UTF-8.

Functions that return position values, such as STRPOS, encode those positions as INT64. The value 1 refers to the first character (or byte), 2 refers to the second, and so on. The value 0 indicates an invalid position. When working on STRING types, the returned positions refer to character positions.

All string comparisons are done byte-by-byte, without regard to Unicode canonical equivalence.

BYTE_LENGTH

BYTE_LENGTH(value)

Description

Returns the length of the STRING or BYTES value in BYTES, regardless of whether the type of the value is STRING or BYTES.

Return type

INT64

Examples

WITH example AS
  (SELECT 'абвгд' AS characters, b'абвгд' AS bytes)

SELECT
  characters,
  BYTE_LENGTH(characters) AS string_example,
  bytes,
  BYTE_LENGTH(bytes) AS bytes_example
FROM example;

+------------+----------------+-------+---------------+
| characters | string_example | bytes | bytes_example |
+------------+----------------+-------+---------------+
| абвгд      | 10             | абвгд | 10            |
+------------+----------------+-------+---------------+

CHAR_LENGTH

CHAR_LENGTH(value)

Description

Returns the length of the STRING in characters.

Return type

INT64

Examples

WITH example AS
  (SELECT 'абвгд' AS characters)

SELECT
  characters,
  CHAR_LENGTH(characters) AS char_length_example
FROM example;

+------------+---------------------+
| characters | char_length_example |
+------------+---------------------+
| абвгд      |                   5 |
+------------+---------------------+

CHARACTER_LENGTH

CHARACTER_LENGTH(value)

Description

Synonym for CHAR_LENGTH.

Return type

INT64

Examples

WITH example AS
  (SELECT 'абвгд' AS characters)

SELECT
  characters,
  CHARACTER_LENGTH(characters) AS char_length_example
FROM example;

+------------+---------------------+
| characters | char_length_example |
+------------+---------------------+
| абвгд      |                   5 |
+------------+---------------------+

CODE_POINTS_TO_BYTES

CODE_POINTS_TO_BYTES(ascii_code_points)

Description

Takes an array of extended ASCII code points as ARRAY<INT64> and returns BYTES.

To convert from BYTES to an array of code points, see TO_CODE_POINTS.

Return type

BYTES

Examples

The following is a basic example using CODE_POINTS_TO_BYTES.

SELECT CODE_POINTS_TO_BYTES([65, 98, 67, 100]) AS bytes;

-- Note that the result of CODE_POINTS_TO_BYTES is of type BYTES, displayed as a base64-encoded string.
-- In BYTES format, b'AbCd' is the result.
+----------+
| bytes    |
+----------+
| QWJDZA== |
+----------+

The following example uses a rotate-by-13 places (ROT13) algorithm to encode a string.

SELECT CODE_POINTS_TO_BYTES(ARRAY(
  (SELECT
      CASE
        WHEN chr BETWEEN b'a' AND b'z'
          THEN TO_CODE_POINTS(b'a')[offset(0)] +
            MOD(code + 13 - TO_CODE_POINTS(b'a')[offset(0)],26)
        WHEN chr BETWEEN b'A' AND b'Z'
          THEN TO_CODE_POINTS(b'A')[offset(0)] +
            MOD(code + 13 - TO_CODE_POINTS(b'A')[offset(0)],26)
        ELSE code
      END
   FROM
     (SELECT code, CODE_POINTS_TO_BYTES(ARRAY[code]) AS chr
      FROM UNNEST(TO_CODE_POINTS(input)) AS code WITH OFFSET
      ORDER BY OFFSET)
   ))) AS encoded_string
FROM UNNEST(ARRAY['Test String!']) AS input;

-- Note that the result of CODE_POINTS_TO_BYTES is of type BYTES, displayed as a base64-encoded string.
-- In BYTES format, b'Grfg Fgevat!' is the result.
+------------------+
| encoded_string   |
+------------------+
| R3JmZyBGZ2V2YXQh |
+------------------+

CODE_POINTS_TO_STRING

CODE_POINTS_TO_STRING(unicode_code_points)

Description

Takes an array of Unicode code points as ARRAY<INT64> and returns a STRING.

To convert from a string to an array of code points, see TO_CODE_POINTS.

Return type

STRING

Examples

The following are basic examples using CODE_POINTS_TO_STRING.

SELECT CODE_POINTS_TO_STRING([65, 255, 513, 1024]) AS string;

+--------+
| string |
+--------+
| AÿȁЀ   |
+--------+

SELECT CODE_POINTS_TO_STRING([97, 0, 0xF9B5]) AS string;

+--------+
| string |
+--------+
| a例    |
+--------+

SELECT CODE_POINTS_TO_STRING([65, 255, NULL, 1024]) AS string;

+--------+
| string |
+--------+
| NULL   |
+--------+

The following example computes the frequency of letters in a set of words.

WITH Words AS (
  SELECT word
  FROM UNNEST(['foo', 'bar', 'baz', 'giraffe', 'llama']) AS word
)
SELECT
  CODE_POINTS_TO_STRING([code_point]) AS letter,
  COUNT(*) AS letter_count
FROM Words,
  UNNEST(TO_CODE_POINTS(word)) AS code_point
GROUP BY 1
ORDER BY 2 DESC;

+--------+--------------+
| letter | letter_count |
+--------+--------------+
| a      | 5            |
| f      | 3            |
| r      | 2            |
| b      | 2            |
| l      | 2            |
| o      | 2            |
| g      | 1            |
| z      | 1            |
| e      | 1            |
| m      | 1            |
| i      | 1            |
+--------+--------------+

CONCAT

CONCAT(value1[, ...])

Description

Concatenates one or more STRING or BYTE values into a single result.

The function returns NULL if any input argument is NULL.

Note: You can also use the || concatenation operator to concatenate values into a string.

Return type

STRING or BYTES

Examples

SELECT CONCAT('T.P.', ' ', 'Bar') as author;

+---------------------+
| author              |
+---------------------+
| T.P. Bar            |
+---------------------+

With Employees AS
  (SELECT
    'John' AS first_name,
    'Doe' AS last_name
  UNION ALL
  SELECT
    'Jane' AS first_name,
    'Smith' AS last_name
  UNION ALL
  SELECT
    'Joe' AS first_name,
    'Jackson' AS last_name)

SELECT
  CONCAT(first_name, ' ', last_name)
  AS full_name
FROM Employees;

+---------------------+
| full_name           |
+---------------------+
| John Doe            |
| Jane Smith          |
| Joe Jackson         |
+---------------------+

ENDS_WITH

ENDS_WITH(value1, value2)

Description

Takes two STRING or BYTES values. Returns TRUE if the second value is a suffix of the first.

Return type

BOOL

Examples

WITH items AS
  (SELECT 'apple' as item
  UNION ALL
  SELECT 'banana' as item
  UNION ALL
  SELECT 'orange' as item)

SELECT
  ENDS_WITH(item, 'e') as example
FROM items;

+---------+
| example |
+---------+
|    True |
|   False |
|    True |
+---------+

FORMAT

FORMAT(format_string_expression, data_type_expression[, ...])

Description

FORMAT formats a data type expression as a string.

• format_string_expression: Can contain zero or more format specifiers. Each format specifier is introduced by the % symbol, and must map to one or more of the remaining arguments. In general, this is a one-to-one mapping, except when the * specifier is present. For example, %.*i maps to two arguments—a length argument and a signed integer argument. If the number of arguments related to the format specifiers is not the same as the number of arguments, an error occurs.
• data_type_expression: The value to format as a string. This can be any GoogleSQL data type.

Return type

STRING

Examples

Description	Statement	Result
Simple integer	FORMAT('%d', 10)	10
Integer with left blank padding	FORMAT('|%10d|', 11)	|           11|
Integer with left zero padding	FORMAT('+%010d+', 12)	+0000000012+
Integer with commas	FORMAT("%'d", 123456789)	123,456,789
STRING	FORMAT('-%s-', 'abcd efg')	-abcd efg-
FLOAT64	FORMAT('%f %E', 1.1, 2.2)	1.100000 2.200000E+00
DATE	FORMAT('%t', date '2015-09-01')	2015-09-01
TIMESTAMP	FORMAT('%t', timestamp '2015-09-01 12:34:56 America/Los_Angeles')	2015‑09‑01 19:34:56+00

The FORMAT() function does not provide fully customizable formatting for all types and values, nor formatting that is sensitive to locale.

If custom formatting is necessary for a type, you must first format it using type-specific format functions, such as FORMAT_DATE() or FORMAT_TIMESTAMP(). For example:

SELECT FORMAT('date: %s!', FORMAT_DATE('%B %d, %Y', date '2015-01-02'));

Returns

date: January 02, 2015!

Supported format specifiers

%[flags][width][.precision]specifier

A format specifier adds formatting when casting a value to a string. It can optionally contain these sub-specifiers:

• Flags
• Width
• Precision

Additional information about format specifiers:

• %g and %G behavior
• %p and %P behavior
• %t and %T behavior
• Error conditions
• NULL argument handling
• Additional semantic rules

Format specifiers

Specifier	Description	Examples	Types
d or i	Decimal integer	392	INT64
o	Octal	610	INT64*
x	Hexadecimal integer	7fa	INT64*
X	Hexadecimal integer (uppercase)	7FA	INT64*
f	Decimal notation, in [-](integer part).(fractional part) for finite values, and in lowercase for non-finite values	392.650000 inf nan	NUMERIC FLOAT64
F	Decimal notation, in [-](integer part).(fractional part) for finite values, and in uppercase for non-finite values	392.650000 INF NAN	NUMERIC FLOAT64
e	Scientific notation (mantissa/exponent), lowercase	3.926500e+02 inf nan	NUMERIC FLOAT64
E	Scientific notation (mantissa/exponent), uppercase	3.926500E+02 INF NAN	NUMERIC FLOAT64
g	Either decimal notation or scientific notation, depending on the input value's exponent and the specified precision. Lowercase. See %g and %G behavior for details.	392.65 3.9265e+07 inf nan	NUMERIC FLOAT64
G	Either decimal notation or scientific notation, depending on the input value's exponent and the specified precision. Uppercase. See %g and %G behavior for details.	392.65 3.9265E+07 INF NAN	NUMERIC FLOAT64
p	Produces a one-line printable string representing JSON. See %p and %P behavior.	{"month":10,"year":2019}	JSON
P	Produces a multi-line printable string representing JSON. See %p and %P behavior.	{ "month": 10, "year": 2019 }	JSON
s	String of characters	sample	STRING
t	Returns a printable string representing the value. Often looks similar to casting the argument to STRING. See %t and %T behavior.	sample 2014‑01‑01	<any>
T	Produces a string that is a valid GoogleSQL constant with a similar type to the value's type (maybe wider, or maybe string). See %t and %T behavior.	'sample' b'bytes sample' 1234 2.3 date '2014‑01‑01'	<any>
%	'%%' produces a single '%'	%	n/a

^*The specifiers %o, %x, and %X raise an error if negative values are used.

The format specifier can optionally contain the sub-specifiers identified above in the specifier prototype.

These sub-specifiers must comply with the following specifications.

Flags

Flags	Description
-	Left-justify within the given field width; Right justification is the default (see width sub-specifier)
+	Forces to precede the result with a plus or minus sign (+ or -) even for positive numbers. By default, only negative numbers are preceded with a - sign
<space>	If no sign is going to be written, a blank space is inserted before the value
#	For `%o`, `%x`, and `%X`, this flag means to precede the value with 0, 0x or 0X respectively for values different than zero. For `%f`, `%F`, `%e`, and `%E`, this flag means to add the decimal point even when there is no fractional part, unless the value is non-finite. For `%g` and `%G`, this flag means to add the decimal point even when there is no fractional part unless the value is non-finite, and never remove the trailing zeros after the decimal point.
0	Left-pads the number with zeroes (0) instead of spaces when padding is specified (see width sub-specifier)
'	Formats integers using the appropriating grouping character. For example: FORMAT("%'d", 12345678) returns 12,345,678 FORMAT("%'x", 12345678) returns bc:614e FORMAT("%'o", 55555) returns 15,4403 This flag is only relevant for decimal, hex, and octal values.

Flags may be specified in any order. Duplicate flags are not an error. When flags are not relevant for some element type, they are ignored.

Width

Width	Description
<number>	Minimum number of characters to be printed. If the value to be printed is shorter than this number, the result is padded with blank spaces. The value is not truncated even if the result is larger
*	The width is not specified in the format string, but as an additional integer value argument preceding the argument that has to be formatted

Precision

Precision	Description
.<number>	For integer specifiers `%d`, `%i`, `%o`, `%u`, `%x`, and `%X`: precision specifies the minimum number of digits to be written. If the value to be written is shorter than this number, the result is padded with trailing zeros. The value is not truncated even if the result is longer. A precision of 0 means that no character is written for the value 0. For specifiers `%a`, `%A`, `%e`, `%E`, `%f`, and `%F`: this is the number of digits to be printed after the decimal point. The default value is 6. For specifiers `%g` and `%G`: this is the number of significant digits to be printed, before the removal of the trailing zeros after the decimal point. The default value is 6.
.*	The precision is not specified in the format string, but as an additional integer value argument preceding the argument that has to be formatted

%g and %G behavior

The %g and %G format specifiers choose either the decimal notation (like the %f and %F specifiers) or the scientific notation (like the %e and %E specifiers), depending on the input value's exponent and the specified precision.

Let p stand for the specified precision (defaults to 6; 1 if the specified precision is less than 1). The input value is first converted to scientific notation with precision = (p - 1). If the resulting exponent part x is less than -4 or no less than p, the scientific notation with precision = (p - 1) is used; otherwise the decimal notation with precision = (p - 1 - x) is used.

Unless # flag is present, the trailing zeros after the decimal point are removed, and the decimal point is also removed if there is no digit after it.

%p and %P behavior

The %p format specifier produces a one-line printable string. The %P format specifier produces a multi-line printable string. You can use these format specifiers with the following data types:

Type	%p	%P
JSON	JSON input: JSON ' { "month": 10, "year": 2019 } ' Produces a one-line printable string representing JSON: {"month":10,"year":2019}	JSON input: JSON ' { "month": 10, "year": 2019 } ' Produces a multi-line printable string representing JSON: { "month": 10, "year": 2019 }

%t and %T behavior

The %t and %T format specifiers are defined for all types. The width, precision, and flags act as they do for %s: the width is the minimum width and the STRING will be padded to that size, and precision is the maximum width of content to show and the STRING will be truncated to that size, prior to padding to width.

The %t specifier is always meant to be a readable form of the value.

The %T specifier is always a valid SQL literal of a similar type, such as a wider numeric type. The literal will not include casts or a type name, except for the special case of non-finite floating point values.

The STRING is formatted as follows:

Type	%t	%T
NULL of any type	NULL	NULL
INT64	123	123
NUMERIC	123.0 (always with .0)	NUMERIC "123.0"
FLOAT64	123.0 (always with .0) 123e+10 inf -inf NaN	123.0 (always with .0) 123e+10 CAST("inf" AS <type>) CAST("-inf" AS <type>) CAST("nan" AS <type>)
STRING	unquoted string value	quoted string literal
BYTES	unquoted escaped bytes e.g. abc\x01\x02	quoted bytes literal e.g. b"abc\x01\x02"
DATE	2011-02-03	DATE "2011-02-03"
TIMESTAMP	2011-02-03 04:05:06+00	TIMESTAMP "2011-02-03 04:05:06+00"
ARRAY	[value, value, ...] where values are formatted with %t	[value, value, ...] where values are formatted with %T
JSON	one-line printable string representing JSON. {"name":"apple","stock":3}	one-line printable string representing a JSON literal. JSON '{"name":"apple","stock":3}'

Error conditions

If a format specifier is invalid, or is not compatible with the related argument type, or the wrong number or arguments are provided, then an error is produced. For example, the following <format_string> expressions are invalid:

FORMAT('%s', 1)

FORMAT('%')

NULL argument handling

A NULL format string results in a NULL output STRING. Any other arguments are ignored in this case.

The function generally produces a NULL value if a NULL argument is present. For example, FORMAT('%i', NULL_expression) produces a NULL STRING as output.

However, there are some exceptions: if the format specifier is %t or %T (both of which produce STRINGs that effectively match CAST and literal value semantics), a NULL value produces 'NULL' (without the quotes) in the result STRING. For example, the function:

FORMAT('00-%t-00', NULL_expression);

Returns

00-NULL-00

Additional semantic rules

FLOAT64 values can be +/-inf or NaN. When an argument has one of those values, the result of the format specifiers %f, %F, %e, %E, %g, %G, and %t are inf, -inf, or nan (or the same in uppercase) as appropriate. This is consistent with how GoogleSQL casts these values to STRING. For %T, GoogleSQL returns quoted strings for FLOAT64 values that don't have non-string literal representations.

FROM_BASE32

FROM_BASE32(string_expr)

Description

Converts the base32-encoded input string_expr into BYTES format. To convert BYTES to a base32-encoded STRING, use TO_BASE32.

Return type

BYTES

Example

SELECT FROM_BASE32('MFRGGZDF74======') AS byte_data;

-- Note that the result of FROM_BASE32 is of type BYTES, displayed as a base64-encoded string.
+-----------+
| byte_data |
+-----------+
| YWJjZGX/  |
+-----------+

FROM_BASE64

FROM_BASE64(string_expr)

Description

Converts the base64-encoded input string_expr into BYTES format. To convert BYTES to a base64-encoded STRING, use [TO_BASE64][string-link-to-base64].

There are several base64 encodings in common use that vary in exactly which alphabet of 65 ASCII characters are used to encode the 64 digits and padding. See RFC 4648 for details. This function expects the alphabet [A-Za-z0-9+/=].

Return type

BYTES

Example

SELECT FROM_BASE64('/+A=') AS byte_data;

-- Note that the result of FROM_BASE64 is of type BYTES, displayed as a base64-encoded string.
+-----------+
| byte_data |
+-----------+
| /+A=      |
+-----------+

To work with an encoding using a different base64 alphabet, you might need to compose FROM_BASE64 with the REPLACE function. For instance, the base64url url-safe and filename-safe encoding commonly used in web programming uses -_= as the last characters rather than +/=. To decode a base64url-encoded string, replace - and _ with + and / respectively.

SELECT FROM_BASE64(REPLACE(REPLACE('_-A=', '-', '+'), '_', '/')) AS binary;

-- Note that the result of FROM_BASE64 is of type BYTES, displayed as a base64-encoded string.
+--------+
| binary |
+--------+
| /+A=   |
+--------+

FROM_HEX

FROM_HEX(string)

Description

Converts a hexadecimal-encoded STRING into BYTES format. Returns an error if the input STRING contains characters outside the range (0..9, A..F, a..f). The lettercase of the characters does not matter. If the input STRING has an odd number of characters, the function acts as if the input has an additional leading 0. To convert BYTES to a hexadecimal-encoded STRING, use TO_HEX.

Return type

BYTES

Example

WITH Input AS (
  SELECT '00010203aaeeefff' AS hex_str UNION ALL
  SELECT '0AF' UNION ALL
  SELECT '666f6f626172'
)
SELECT hex_str, FROM_HEX(hex_str) AS bytes_str
FROM Input;

-- Note that the result of FROM_HEX is of type BYTES, displayed as a base64-encoded string.
+------------------+--------------+
| hex_str          | bytes_str    |
+------------------+--------------+
| 0AF              | AAECA6ru7/8= |
| 00010203aaeeefff | AK8=         |
| 666f6f626172     | Zm9vYmFy     |
+------------------+--------------+

LENGTH

LENGTH(value)

Description

Returns the length of the STRING or BYTES value. The returned value is in characters for STRING arguments and in bytes for the BYTES argument.

Return type

INT64

Examples

WITH example AS
  (SELECT 'абвгд' AS characters)

SELECT
  characters,
  LENGTH(characters) AS string_example,
  LENGTH(CAST(characters AS BYTES)) AS bytes_example
FROM example;

+------------+----------------+---------------+
| characters | string_example | bytes_example |
+------------+----------------+---------------+
| абвгд      |              5 |            10 |
+------------+----------------+---------------+

LOWER

LOWER(value)

Description

For STRING arguments, returns the original string with all alphabetic characters in lowercase. Mapping between lowercase and uppercase is done according to the Unicode Character Database without taking into account language-specific mappings.

For BYTES arguments, the argument is treated as ASCII text, with all bytes greater than 127 left intact.

Return type

STRING or BYTES

Examples

WITH items AS
  (SELECT
    'FOO' as item
  UNION ALL
  SELECT
    'BAR' as item
  UNION ALL
  SELECT
    'BAZ' as item)

SELECT
  LOWER(item) AS example
FROM items;

+---------+
| example |
+---------+
| foo     |
| bar     |
| baz     |
+---------+

LPAD

LPAD(original_value, return_length[, pattern])

Description

Returns a STRING or BYTES value that consists of original_value prepended with pattern. The return_length is an INT64 that specifies the length of the returned value. If original_value is of type BYTES, return_length is the number of bytes. If original_value is of type STRING, return_length is the number of characters.

The default value of pattern is a blank space.

Both original_value and pattern must be the same data type.

If return_length is less than or equal to the original_value length, this function returns the original_value value, truncated to the value of return_length. For example, LPAD('hello world', 7); returns 'hello w'.

If original_value, return_length, or pattern is NULL, this function returns NULL.

This function returns an error if:

• return_length is negative
• pattern is empty

Return type

STRING or BYTES

Examples

SELECT t, len, FORMAT('%T', LPAD(t, len)) AS LPAD FROM UNNEST([
  STRUCT('abc' AS t, 5 AS len),
  ('abc', 2),
  ('例子', 4)
]);

+------+-----+----------+
| t    | len | LPAD     |
|------|-----|----------|
| abc  | 5   | "  abc"  |
| abc  | 2   | "ab"     |
| 例子  | 4   | "  例子" |
+------+-----+----------+

SELECT t, len, pattern, FORMAT('%T', LPAD(t, len, pattern)) AS LPAD FROM UNNEST([
  STRUCT('abc' AS t, 8 AS len, 'def' AS pattern),
  ('abc', 5, '-'),
  ('例子', 5, '中文')
]);

+------+-----+---------+--------------+
| t    | len | pattern | LPAD         |
|------|-----|---------|--------------|
| abc  | 8   | def     | "defdeabc"   |
| abc  | 5   | -       | "--abc"      |
| 例子  | 5   | 中文    | "中文中例子"   |
+------+-----+---------+--------------+

SELECT FORMAT('%T', t) AS t, len, FORMAT('%T', LPAD(t, len)) AS LPAD FROM UNNEST([
  STRUCT(b'abc' AS t, 5 AS len),
  (b'abc', 2),
  (b'\xab\xcd\xef', 4)
]);

+-----------------+-----+------------------+
| t               | len | LPAD             |
|-----------------|-----|------------------|
| b"abc"          | 5   | b"  abc"         |
| b"abc"          | 2   | b"ab"            |
| b"\xab\xcd\xef" | 4   | b" \xab\xcd\xef" |
+-----------------+-----+------------------+

SELECT
  FORMAT('%T', t) AS t,
  len,
  FORMAT('%T', pattern) AS pattern,
  FORMAT('%T', LPAD(t, len, pattern)) AS LPAD
FROM UNNEST([
  STRUCT(b'abc' AS t, 8 AS len, b'def' AS pattern),
  (b'abc', 5, b'-'),
  (b'\xab\xcd\xef', 5, b'\x00')
]);

+-----------------+-----+---------+-------------------------+
| t               | len | pattern | LPAD                    |
|-----------------|-----|---------|-------------------------|
| b"abc"          | 8   | b"def"  | b"defdeabc"             |
| b"abc"          | 5   | b"-"    | b"--abc"                |
| b"\xab\xcd\xef" | 5   | b"\x00" | b"\x00\x00\xab\xcd\xef" |
+-----------------+-----+---------+-------------------------+

LTRIM

LTRIM(value1[, value2])

Description

Identical to TRIM, but only removes leading characters.

Return type

STRING or BYTES

Examples

WITH items AS
  (SELECT '   apple   ' as item
  UNION ALL
  SELECT '   banana   ' as item
  UNION ALL
  SELECT '   orange   ' as item)

SELECT
  CONCAT('#', LTRIM(item), '#') as example
FROM items;

+-------------+
| example     |
+-------------+
| #apple   #  |
| #banana   # |
| #orange   # |
+-------------+

WITH items AS
  (SELECT '***apple***' as item
  UNION ALL
  SELECT '***banana***' as item
  UNION ALL
  SELECT '***orange***' as item)

SELECT
  LTRIM(item, '*') as example
FROM items;

+-----------+
| example   |
+-----------+
| apple***  |
| banana*** |
| orange*** |
+-----------+

WITH items AS
  (SELECT 'xxxapplexxx' as item
  UNION ALL
  SELECT 'yyybananayyy' as item
  UNION ALL
  SELECT 'zzzorangezzz' as item
  UNION ALL
  SELECT 'xyzpearxyz' as item)

SELECT
  LTRIM(item, 'xyz') as example
FROM items;

+-----------+
| example   |
+-----------+
| applexxx  |
| bananayyy |
| orangezzz |
| pearxyz   |
+-----------+

NORMALIZE_AND_CASEFOLD

NORMALIZE_AND_CASEFOLD(value[, normalization_mode])

Description

Takes a string value and returns it as a normalized string. If you do not provide a normalization mode, NFC is used.

Normalization is used to ensure that two strings are equivalent. Normalization is often used in situations in which two strings render the same on the screen but have different Unicode code points.

Case folding is used for the caseless comparison of strings. If you need to compare strings and case should not be considered, use NORMALIZE_AND_CASEFOLD, otherwise use NORMALIZE.

NORMALIZE_AND_CASEFOLD supports four optional normalization modes:

Value	Name	Description
NFC	Normalization Form Canonical Composition	Decomposes and recomposes characters by canonical equivalence.
NFKC	Normalization Form Compatibility Composition	Decomposes characters by compatibility, then recomposes them by canonical equivalence.
NFD	Normalization Form Canonical Decomposition	Decomposes characters by canonical equivalence, and multiple combining characters are arranged in a specific order.
NFKD	Normalization Form Compatibility Decomposition	Decomposes characters by compatibility, and multiple combining characters are arranged in a specific order.

Return type

STRING

Examples

SELECT
  a, b,
  NORMALIZE(a) = NORMALIZE(b) as normalized,
  NORMALIZE_AND_CASEFOLD(a) = NORMALIZE_AND_CASEFOLD(b) as normalized_with_case_folding
FROM (SELECT 'The red barn' AS a, 'The Red Barn' AS b);

+--------------+--------------+------------+------------------------------+
| a            | b            | normalized | normalized_with_case_folding |
+--------------+--------------+------------+------------------------------+
| The red barn | The Red Barn | false      | true                         |
+--------------+--------------+------------+------------------------------+

WITH Strings AS (
  SELECT '\u2168' AS a, 'IX' AS b UNION ALL
  SELECT '\u0041\u030A', '\u00C5'
)
SELECT a, b,
  NORMALIZE_AND_CASEFOLD(a, NFD)=NORMALIZE_AND_CASEFOLD(b, NFD) AS nfd,
  NORMALIZE_AND_CASEFOLD(a, NFC)=NORMALIZE_AND_CASEFOLD(b, NFC) AS nfc,
  NORMALIZE_AND_CASEFOLD(a, NFKD)=NORMALIZE_AND_CASEFOLD(b, NFKD) AS nkfd,
  NORMALIZE_AND_CASEFOLD(a, NFKC)=NORMALIZE_AND_CASEFOLD(b, NFKC) AS nkfc
FROM Strings;

+---+----+-------+-------+------+------+
| a | b  | nfd   | nfc   | nkfd | nkfc |
+---+----+-------+-------+------+------+
| Ⅸ | IX | false | false | true | true |
| Å | Å  | true  | true  | true | true |
+---+----+-------+-------+------+------+

NORMALIZE

NORMALIZE(value[, normalization_mode])

Description

Takes a string value and returns it as a normalized string. If you do not provide a normalization mode, NFC is used.

Normalization is used to ensure that two strings are equivalent. Normalization is often used in situations in which two strings render the same on the screen but have different Unicode code points.

NORMALIZE supports four optional normalization modes:

Value	Name	Description
NFC	Normalization Form Canonical Composition	Decomposes and recomposes characters by canonical equivalence.
NFKC	Normalization Form Compatibility Composition	Decomposes characters by compatibility, then recomposes them by canonical equivalence.
NFD	Normalization Form Canonical Decomposition	Decomposes characters by canonical equivalence, and multiple combining characters are arranged in a specific order.
NFKD	Normalization Form Compatibility Decomposition	Decomposes characters by compatibility, and multiple combining characters are arranged in a specific order.

Return type

STRING

Examples

SELECT a, b, a = b as normalized
FROM (SELECT NORMALIZE('\u00ea') as a, NORMALIZE('\u0065\u0302') as b);

+---+---+------------+
| a | b | normalized |
+---+---+------------+
| ê | ê | true       |
+---+---+------------+

The following example normalizes different space characters.

WITH EquivalentNames AS (
  SELECT name
  FROM UNNEST([
      'Jane\u2004Doe',
      'John\u2004Smith',
      'Jane\u2005Doe',
      'Jane\u2006Doe',
      'John Smith']) AS name
)
SELECT
  NORMALIZE(name, NFKC) AS normalized_name,
  COUNT(*) AS name_count
FROM EquivalentNames
GROUP BY 1;

+-----------------+------------+
| normalized_name | name_count |
+-----------------+------------+
| John Smith      | 2          |
| Jane Doe        | 3          |
+-----------------+------------+

REGEXP_CONTAINS

REGEXP_CONTAINS(value, regexp)

Description

Returns TRUE if value is a partial match for the regular expression, regexp.

If the regexp argument is invalid, the function returns an error.

You can search for a full match by using ^ (beginning of text) and $ (end of text). Due to regular expression operator precedence, it is good practice to use parentheses around everything between ^ and $.

Note: GoogleSQL provides regular expression support using the re2 library; see that documentation for its regular expression syntax.

Return type

BOOL

Examples

SELECT
  email,
  REGEXP_CONTAINS(email, r'@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+') AS is_valid
FROM
  (SELECT
    ['[e-mail]', '[e-mail]', 'www.example.net']
    AS addresses),
  UNNEST(addresses) AS email;

+-----------------+----------+
| email           | is_valid |
+-----------------+----------+
| [e-mail] | true     |
| [e-mail] | true     |
| www.example.net | false    |
+-----------------+----------+

-- Performs a full match, using ^ and $. Due to regular expression operator
-- precedence, it is good practice to use parentheses around everything between ^
-- and $.
SELECT
  email,
  REGEXP_CONTAINS(email, r'^([\w.+-]+@foo\.com|[\w.+-]+@bar\.org)$')
    AS valid_email_address,
  REGEXP_CONTAINS(email, r'^[\w.+-]+@foo\.com|[\w.+-]+@bar\.org$')
    AS without_parentheses
FROM
  (SELECT
    ['[e-mail]', '[e-mail]', '[e-mail]', '![e-mail]', '[e-mail]']
    AS addresses),
  UNNEST(addresses) AS email;

+----------------+---------------------+---------------------+
| email          | valid_email_address | without_parentheses |
+----------------+---------------------+---------------------+
| [e-mail]      | true                | true                |
| [e-mail] | false               | true                |
| [e-mail]      | true                | true                |
| ![e-mail]     | false               | true                |
| [e-mail]      | false               | false               |
+----------------+---------------------+---------------------+

REGEXP_EXTRACT_ALL

REGEXP_EXTRACT_ALL(value, regexp)

Description

Returns an array of all substrings of value that match the re2 regular expression, regexp. Returns an empty array if there is no match.

If the regular expression contains a capturing group ((...)), and there is a match for that capturing group, that match is added to the results. If there are multiple matches for a capturing group, the last match is added to the results.

The REGEXP_EXTRACT_ALL function only returns non-overlapping matches. For example, using this function to extract ana from banana returns only one substring, not two.

Returns an error if:

• The regular expression is invalid
• The regular expression has more than one capturing group

Return type

ARRAY<STRING> or ARRAY<BYTES>

Examples

WITH code_markdown AS
  (SELECT 'Try `function(x)` or `function(y)`' as code)

SELECT
  REGEXP_EXTRACT_ALL(code, '`(.+?)`') AS example
FROM code_markdown;

+----------------------------+
| example                    |
+----------------------------+
| [function(x), function(y)] |
+----------------------------+

REGEXP_EXTRACT

REGEXP_EXTRACT(value, regexp)

Description

Returns the first substring in value that matches the re2 regular expression, regexp. Returns NULL if there is no match.

If the regular expression contains a capturing group ((...)), and there is a match for that capturing group, that match is returned. If there are multiple matches for a capturing group, the last match is returned.

Returns an error if:

• The regular expression is invalid
• The regular expression has more than one capturing group

Return type

STRING or BYTES

Examples

WITH email_addresses AS
  (SELECT '[e-mail]' as email
  UNION ALL
  SELECT '[e-mail]' as email
  UNION ALL
  SELECT '[e-mail]' as email)

SELECT
  REGEXP_EXTRACT(email, r'^[a-zA-Z0-9_.+-]+')
  AS user_name
FROM email_addresses;

+-----------+
| user_name |
+-----------+
| foo       |
| bar       |
| baz       |
+-----------+

WITH email_addresses AS
  (SELECT '[e-mail]' as email
  UNION ALL
  SELECT '[e-mail]' as email
  UNION ALL
  SELECT '[e-mail]' as email)

SELECT
  REGEXP_EXTRACT(email, r'^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.([a-zA-Z0-9-.]+$)')
  AS top_level_domain
FROM email_addresses;

+------------------+
| top_level_domain |
+------------------+
| com              |
| org              |
| net              |
+------------------+

WITH
  characters AS (
    SELECT 'ab' AS value, '.b' AS regex UNION ALL
    SELECT 'ab' AS value, '(.)b' AS regex UNION ALL
    SELECT 'xyztb' AS value, '(.)+b' AS regex UNION ALL
    SELECT 'ab' AS value, '(z)?b' AS regex
  )
SELECT value, regex, REGEXP_EXTRACT(value, regex) AS result FROM characters;

+-------+---------+----------+
| value | regex   | result   |
+-------+---------+----------+
| ab    | .b      | ab       |
| ab    | (.)b    | a        |
| xyztb | (.)+b   | t        |
| ab    | (z)?b   | NULL     |
+-------+---------+----------+

REGEXP_REPLACE

REGEXP_REPLACE(value, regexp, replacement)

Description

Returns a STRING where all substrings of value that match regular expression regexp are replaced with replacement.

You can use backslashed-escaped digits (\1 to \9) within the replacement argument to insert text matching the corresponding parenthesized group in the regexp pattern. Use \0 to refer to the entire matching text.

To add a backslash in your regular expression, you must first escape it. For example, SELECT REGEXP_REPLACE('abc', 'b(.)', 'X\\1'); returns aXc. You can also use raw strings to remove one layer of escaping, for example SELECT REGEXP_REPLACE('abc', 'b(.)'