Conversion functions

GoogleSQL for BigQuery 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.

Function list

Name	Summary
`ARRAY_TO_STRING`	Produces a concatenation of the elements in an array as a `STRING` value. For more information, see Array functions.
`BOOL`	Converts a JSON boolean to a SQL `BOOL` value. For more information, see JSON functions.
`CAST`	Convert the results of an expression to the given type.
`CHR`	Converts a Unicode code point to a character. For more information, see String functions.
`CODE_POINTS_TO_BYTES`	Converts an array of extended ASCII code points to a `BYTES` value. For more information, see String aggregate functions.
`CODE_POINTS_TO_STRING`	Converts an array of extended ASCII code points to a `STRING` value. For more information, see String aggregate functions.
`DATE_FROM_UNIX_DATE`	Interprets an `INT64` expression as the number of days since 1970-01-01. For more information, see Date functions.
`FROM_BASE32`	Converts a base32-encoded `STRING` value into a `BYTES` value. For more information, see String functions.
`FROM_BASE64`	Converts a base64-encoded `STRING` value into a `BYTES` value. For more information, see String functions.
`FROM_HEX`	Converts a hexadecimal-encoded `STRING` value into a `BYTES` value. For more information, see String functions.
`INT64`	Converts a JSON number to a SQL `INT64` value. For more information, see JSON functions.
`LAX_BOOL`	Attempts to convert a JSON value to a SQL `BOOL` value. For more information, see JSON functions.
`LAX_FLOAT64`	Attempts to convert a JSON value to a SQL `FLOAT64` value. For more information, see JSON functions.
`LAX_INT64`	Attempts to convert a JSON value to a SQL `INT64` value. For more information, see JSON functions.
`LAX_STRING`	Attempts to convert a JSON value to a SQL `STRING` value. For more information, see JSON functions.
`PARSE_BIGNUMERIC`	Converts a `STRING` value to a `BIGNUMERIC` value.
`PARSE_DATE`	Converts a `STRING` value to a `DATE` value. For more information, see Date functions.
`PARSE_DATETIME`	Converts a `STRING` value to a `DATETIME` value. For more information, see Datetime functions.
`PARSE_JSON`	Converts a JSON-formatted `STRING` value to a `JSON` value. For more information, see JSON functions.
`PARSE_NUMERIC`	Converts a `STRING` value to a `NUMERIC` value.
`PARSE_TIME`	Converts a `STRING` value to a `TIME` value. For more information, see Time functions.
`PARSE_TIMESTAMP`	Converts a `STRING` value to a `TIMESTAMP` value. For more information, see Timestamp functions.
`SAFE_CAST`	Similar to the `CAST` function, but returns `NULL` when a runtime error is produced.
`SAFE_CONVERT_BYTES_TO_STRING`	Converts a `BYTES` value to a `STRING` value and replace any invalid UTF-8 characters with the Unicode replacement character, `U+FFFD`. For more information, see String functions.
`STRING` (JSON)	Converts a JSON string to a SQL `STRING` value. For more information, see JSON functions.
`STRING` (Timestamp)	Converts a `TIMESTAMP` value to a `STRING` value. For more information, see Timestamp functions.
`TIMESTAMP_MICROS`	Converts the number of microseconds since 1970-01-01 00:00:00 UTC to a `TIMESTAMP`. For more information, see Timestamp functions.
`TIMESTAMP_MILLIS`	Converts the number of milliseconds since 1970-01-01 00:00:00 UTC to a `TIMESTAMP`. For more information, see Timestamp functions.
`TIMESTAMP_SECONDS`	Converts the number of seconds since 1970-01-01 00:00:00 UTC to a `TIMESTAMP`. For more information, see Timestamp functions.
`TO_BASE32`	Converts a `BYTES` value to a base32-encoded `STRING` value. For more information, see String functions.
`TO_BASE64`	Converts a `BYTES` value to a base64-encoded `STRING` value. For more information, see String functions.
`TO_CODE_POINTS`	Converts a `STRING` or `BYTES` value into an array of extended ASCII code points. For more information, see String functions.
`TO_HEX`	Converts a `BYTES` value to a hexadecimal `STRING` value. For more information, see String functions.
`TO_JSON`	Converts a SQL value to a JSON value. For more information, see JSON functions.
`TO_JSON_STRING`	Converts a SQL value to a JSON-formatted `STRING` value. For more information, see JSON functions.
`UNIX_DATE`	Converts a `DATE` value to the number of days since 1970-01-01. For more information, see Date functions.
`UNIX_MICROS`	Converts a `TIMESTAMP` value to the number of microseconds since 1970-01-01 00:00:00 UTC. For more information, see Timestamp functions.
`UNIX_MILLIS`	Converts a `TIMESTAMP` value to the number of milliseconds since 1970-01-01 00:00:00 UTC. For more information, see Timestamp functions.
`UNIX_SECONDS`	Converts a `TIMESTAMP` value to the number of seconds since 1970-01-01 00:00:00 UTC. For more information, see Timestamp functions.

`CAST`

CAST(expression AS typename [format_clause])

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.

Some casts can include a format clause, which provides instructions for how to conduct the cast. For example, you could instruct a cast to convert a sequence of bytes to a BASE64-encoded string instead of a UTF-8-encoded string.

The structure of the format clause is unique to each type of cast and more information is available in the section for that cast.

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 BIGNUMERIC

CAST(expression AS BIGNUMERIC)

Description

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

INT64
FLOAT64
NUMERIC
BIGNUMERIC
STRING

Conversion rules

From	To	Rule(s) when casting `x`
FLOAT64	`BIGNUMERIC`	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 `BIGNUMERIC` returns an overflow error.
`STRING`	`BIGNUMERIC`	The numeric literal contained in the string must not exceed the maximum precision or range of the `BIGNUMERIC` type, or an error will occur. If the number of digits after the decimal point exceeds 38, then the resulting `BIGNUMERIC` value will round half away from zero to have 38 digits after the decimal point.

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 [format_clause])

Description

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

BYTES
STRING

Format clause

When an expression of one type is cast to another type, you can use the format clause to provide instructions for how to conduct the cast. You can use the format clause in this section if expression is a STRING.

Format string as bytes

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 [format_clause])

Description

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

STRING
DATETIME
TIMESTAMP

Format clause

Format string as date and time

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 DATETIME

CAST(expression AS DATETIME [format_clause])

Description

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

STRING
DATETIME
TIMESTAMP

Format clause

Format string as date and time

Conversion rules

From	To	Rule(s) when casting `x`
`STRING`	`DATETIME`	When casting from string to datetime, the string must conform to the supported datetime literal format, and is independent of time zone. If the string expression is invalid or represents a datetime that is outside of the supported min/max range, then an error is produced.
`TIMESTAMP`	`DATETIME`	Casting from a timestamp to datetime 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
BIGNUMERIC
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.
`BIGNUMERIC`	FLOAT64	`BIGNUMERIC` 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
BIGNUMERIC
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 INTERVAL

CAST(expression AS INTERVAL)

Description

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

STRING

Conversion rules

From	To	Rule(s) when casting `x`
`STRING`	`INTERVAL`	When casting from string to interval, the string must conform to either ISO 8601 Duration standard or to interval literal format 'Y-M D H:M:S.F'. Partial interval literal formats are also accepted when they are not ambiguous, for example 'H:M:S'. If the string expression is invalid or represents an interval that is outside of the supported min/max range, then an error is produced.

Examples

SELECT input, CAST(input AS INTERVAL) AS output
FROM UNNEST([
  '1-2 3 10:20:30.456',
  '1-2',
  '10:20:30',
  'P1Y2M3D',
  'PT10H20M30,456S'
]) input

/*--------------------+--------------------*
 | input              | output             |
 +--------------------+--------------------+
 | 1-2 3 10:20:30.456 | 1-2 3 10:20:30.456 |
 | 1-2                | 1-2 0 0:0:0        |
 | 10:20:30           | 0-0 0 10:20:30     |
 | P1Y2M3D            | 1-2 3 0:0:0        |
 | PT10H20M30,456S    | 0-0 0 10:20:30.456 |
 *--------------------+--------------------*/

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
BIGNUMERIC
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 RANGE

CAST(expression AS RANGE)

Description

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

STRING

Conversion rules

From	To	Rule(s) when casting `x`
`STRING`	`RANGE`	When casting from string to range, the string must conform to the supported range literal format. If the string expression is invalid or represents a range that is outside of the supported subtype min/max range, then an error is produced.

Examples

SELECT CAST(
  '[2020-01-01, 2020-01-02)'
  AS RANGE<DATE>) AS string_to_range

/*----------------------------------------*
 | string_to_range                        |
 +----------------------------------------+
 | [DATE '2020-01-01', DATE '2020-01-02') |
 *----------------------------------------*/

SELECT CAST(
  '[2014-09-27 12:30:00.45, 2016-10-17 11:15:00.33)'
  AS RANGE<DATETIME>) AS string_to_range

/*------------------------------------------------------------------------*
 | string_to_range                                                        |
 +------------------------------------------------------------------------+
 | [DATETIME '2014-09-27 12:30:00.45', DATETIME '2016-10-17 11:15:00.33') |
 *------------------------------------------------------------------------*/

SELECT CAST(
  '[2014-09-27 12:30:00+08, 2016-10-17 11:15:00+08)'
  AS RANGE<TIMESTAMP>) AS string_to_range

-- Results depend upon where this query was executed.
/*---------------------------------------------------------------------------*
 | string_to_range                                                           |
 +---------------------------------------------------------------------------+
 | [TIMESTAMP '2014-09-27 12:30:00+08', TIMESTAMP '2016-10-17 11:15:00 UTC') |
 *---------------------------------------------------------------------------*/

SELECT CAST(
  '[UNBOUNDED, 2020-01-02)'
  AS RANGE<DATE>) AS string_to_range

/*--------------------------------*
 | string_to_range                |
 +--------------------------------+
 | [UNBOUNDED, DATE '2020-01-02') |
 *--------------------------------*/

SELECT CAST(
  '[2020-01-01, NULL)'
  AS RANGE<DATE>) AS string_to_range

/*--------------------------------*
 | string_to_range                |
 +--------------------------------+
 | [DATE '2020-01-01', UNBOUNDED) |
 *--------------------------------*/

CAST AS STRING

CAST(expression AS STRING [format_clause [AT TIME ZONE timezone_expr]])

Description

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

INT64
FLOAT64
NUMERIC
BIGNUMERIC
BOOL
BYTES
TIME
DATE
DATETIME
TIMESTAMP
RANGE
INTERVAL
STRING

Format clause

INT64
FLOAT64
NUMERIC
BIGNUMERIC
BYTES
TIME
DATE
DATETIME
TIMESTAMP

The format clause for STRING has an additional optional clause called AT TIME ZONE timezone_expr, which you can use to specify a specific time zone to use during formatting of a TIMESTAMP. If this optional clause is not included when formatting a TIMESTAMP, your current time zone is used.

For more information, see the following topics:

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.
`TIME`	`STRING`	Casting from a time type to a string is independent of time zone and is of the form `HH:MM:SS`.
`DATE`	`STRING`	Casting from a date type to a string is independent of time zone and is of the form `YYYY-MM-DD`.
`DATETIME`	`STRING`	Casting from a datetime type to a string is independent of time zone and is of the form `YYYY-MM-DD HH:MM:SS`.
`TIMESTAMP`	`STRING`	When casting from timestamp types to string, the timestamp is interpreted using the default time zone, UTC. 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.
`INTERVAL`	`STRING`	Casting from an interval to a string is of the form `Y-M D H:M:S`.

Examples

SELECT CAST(CURRENT_DATE() AS STRING) AS current_date

/*---------------*
 | current_date  |
 +---------------+
 | 2021-03-09    |
 *---------------*/

SELECT CAST(CURRENT_DATE() AS STRING FORMAT 'DAY') AS current_day

/*-------------*
 | current_day |
 +-------------+
 | MONDAY      |
 *-------------*/

SELECT CAST(
  TIMESTAMP '2008-12-25 00:00:00+00:00'
  AS STRING FORMAT 'YYYY-MM-DD HH24:MI:SS TZH:TZM') AS date_time_to_string

-- Results depend upon where this query was executed.
/*------------------------------*
 | date_time_to_string          |
 +------------------------------+
 | 2008-12-24 16:00:00 -08:00   |
 *------------------------------*/

SELECT CAST(
  TIMESTAMP '2008-12-25 00:00:00+00:00'
  AS STRING FORMAT 'YYYY-MM-DD HH24:MI:SS TZH:TZM'
  AT TIME ZONE 'Asia/Kolkata') AS date_time_to_string

-- Because the time zone is specified, the result is always the same.
/*------------------------------*
 | date_time_to_string          |
 +------------------------------+
 | 2008-12-25 05:30:00 +05:30   |
 *------------------------------*/

SELECT CAST(INTERVAL 3 DAY AS STRING) AS interval_to_string

/*--------------------*
 | interval_to_string |
 +--------------------+
 | 0-0 3 0:0:0        |
 *--------------------*/

SELECT CAST(
  INTERVAL "1-2 3 4:5:6.789" YEAR TO SECOND
  AS STRING) AS interval_to_string

/*--------------------*
 | interval_to_string |
 +--------------------+
 | 1-2 3 4:5:6.789    |
 *--------------------*/

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 TIME

CAST(expression AS TIME [format_clause])

Description

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

STRING
TIME
DATETIME
TIMESTAMP

Format clause

Format string as date and time

Conversion rules

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

CAST AS TIMESTAMP

CAST(expression AS TIMESTAMP [format_clause [AT TIME ZONE timezone_expr]])

Description

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

STRING
DATETIME
TIMESTAMP

Format clause

Format string as date and time

The format clause for TIMESTAMP has an additional optional clause called AT TIME ZONE timezone_expr, which you can use to specify a specific time zone to use during formatting. If this optional clause is not included, your current time zone is used.

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, UTC, 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, UTC.
`DATETIME`	`TIMESTAMP`	Casting from a datetime to a timestamp interprets `datetime_expression` in the default time zone, UTC. Most valid datetime values have exactly one corresponding timestamp in each time zone. However, there are certain combinations of valid datetime values and time zones that have zero or two corresponding timestamp values. This happens in a time zone when clocks are set forward or set back, such as for Daylight Savings Time. When there are two valid timestamps, the earlier one is used. When there is no valid timestamp, the length of the gap in time (typically one hour) is added to the datetime.

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                |
 +-----------------------------+
 | 2020-06-03 00:00:53.110 UTC |
 *-----------------------------*/

The following examples cast a string-formatted date and time as a timestamp. These examples return the same output as the previous example.

SELECT CAST('06/02/2020 17:00:53.110' AS TIMESTAMP FORMAT 'MM/DD/YYYY HH24:MI:SS.FF3' AT TIME ZONE 'UTC') AS as_timestamp

SELECT CAST('06/02/2020 17:00:53.110' AS TIMESTAMP FORMAT 'MM/DD/YYYY HH24:MI:SS.FF3' AT TIME ZONE '+00') AS as_timestamp

SELECT CAST('06/02/2020 17:00:53.110 +00' AS TIMESTAMP FORMAT 'MM/DD/YYYY HH24:MI:SS.FF3 TZH') AS as_timestamp

`PARSE_BIGNUMERIC`

PARSE_BIGNUMERIC(string_expression)

Description

Converts a STRING to a BIGNUMERIC value.

The numeric literal contained in the string must not exceed the maximum precision or range of the BIGNUMERIC type, or an error occurs. If the number of digits after the decimal point exceeds 38, then the resulting BIGNUMERIC value rounds half away from zero to have 38 digits after the decimal point.


-- This example shows how a string with a decimal point is parsed.
SELECT PARSE_BIGNUMERIC("123.45") AS parsed;

/*--------*
 | parsed |
 +--------+
 | 123.45 |
 *--------*/

-- This example shows how a string with an exponent is parsed.
SELECT PARSE_BIGNUMERIC("123.456E37") AS parsed;

/*-----------------------------------------*
 | parsed                                  |
 +-----------------------------------------+
 | 123400000000000000000000000000000000000 |
 *-----------------------------------------*/

-- This example shows the rounding when digits after the decimal point exceeds 38.
SELECT PARSE_BIGNUMERIC("1.123456789012345678901234567890123456789") as parsed;

/*------------------------------------------*
 | parsed                                   |
 +------------------------------------------+
 | 1.12345678901234567890123456789012345679 |
 *------------------------------------------*/

This function is similar to using the CAST AS BIGNUMERIC function except that the PARSE_BIGNUMERIC function only accepts string inputs and allows the following in the string:

Spaces between the sign (+/-) and the number
Signs (+/-) after the number

Rules for valid input strings:

Rule	Example Input	Output
The string can only contain digits, commas, decimal points and signs.	"- 12,34567,89.0"	-123456789
Whitespaces are allowed anywhere except between digits.	" - 12.345 "	-12.345
Only digits and commas are allowed before the decimal point.	" 12,345,678"	12345678
Only digits are allowed after the decimal point.	"1.234 "	1.234
Use `E` or `e` for exponents. After the `e`, digits and a leading sign indicator are allowed.	" 123.45e-1"	12.345
If the integer part is not empty, then it must contain at least one digit.	" 0,.12 -"	-0.12
If the string contains a decimal point, then it must contain at least one digit.	" .1"	0.1
The string cannot contain more than one sign.	" 0.5 +"	0.5

Return Data Type

BIGNUMERIC

Examples

This example shows an input with spaces before, after, and between the sign and the number:

SELECT PARSE_BIGNUMERIC("  -  12.34 ") as parsed;

/*--------*
 | parsed |
 +--------+
 | -12.34 |
 *--------*/

This example shows an input with an exponent as well as the sign after the number:

SELECT PARSE_BIGNUMERIC("12.34e-1-") as parsed;

/*--------*
 | parsed |
 +--------+
 | -1.234 |
 *--------*/

This example shows an input with multiple commas in the integer part of the number:

SELECT PARSE_BIGNUMERIC("  1,2,,3,.45 + ") as parsed;

/*--------*
 | parsed |
 +--------+
 | 123.45 |
 *--------*/

This example shows an input with a decimal point and no digits in the whole number part:

SELECT PARSE_BIGNUMERIC(".1234  ") as parsed;

/*--------*
 | parsed |
 +--------+
 | 0.1234 |
 *--------*/

Examples of invalid inputs

This example is invalid because the whole number part contains no digits:

SELECT PARSE_BIGNUMERIC(",,,.1234  ") as parsed;

This example is invalid because there are whitespaces between digits:

SELECT PARSE_BIGNUMERIC("1  23.4 5  ") as parsed;

This example is invalid because the number is empty except for an exponent:

SELECT PARSE_BIGNUMERIC("  e1 ") as parsed;

This example is invalid because the string contains multiple signs:

SELECT PARSE_BIGNUMERIC("  - 12.3 - ") as parsed;

This example is invalid because the value of the number falls outside the range of BIGNUMERIC:

SELECT PARSE_BIGNUMERIC("12.34E100 ") as parsed;

This example is invalid because the string contains invalid characters:

SELECT PARSE_BIGNUMERIC("$12.34") as parsed;

`PARSE_NUMERIC`

PARSE_NUMERIC(string_expression)

Description

Converts a STRING to a NUMERIC value.

The numeric literal contained in the string must not exceed the maximum precision or range of the NUMERIC type, or an error occurs. If the number of digits after the decimal point exceeds nine, then the resulting NUMERIC value rounds half away from zero to have nine digits after the decimal point.


-- This example shows how a string with a decimal point is parsed.
SELECT PARSE_NUMERIC("123.45") AS parsed;

/*--------*
 | parsed |
 +--------+
 | 123.45 |
 *--------*/

-- This example shows how a string with an exponent is parsed.
SELECT PARSE_NUMERIC("12.34E27") as parsed;

/*-------------------------------*
 | parsed                        |
 +-------------------------------+
 | 12340000000000000000000000000 |
 *-------------------------------*/

-- This example shows the rounding when digits after the decimal point exceeds 9.
SELECT PARSE_NUMERIC("1.0123456789") as parsed;

/*-------------*
 | parsed      |
 +-------------+
 | 1.012345679 |
 *-------------*/

This function is similar to using the CAST AS NUMERIC function except that the PARSE_NUMERIC function only accepts string inputs and allows the following in the string:

Spaces between the sign (+/-) and the number
Signs (+/-) after the number

Rules for valid input strings:

Rule	Example Input	Output
The string can only contain digits, commas, decimal points and signs.	"- 12,34567,89.0"	-123456789
Whitespaces are allowed anywhere except between digits.	" - 12.345 "	-12.345
Only digits and commas are allowed before the decimal point.	" 12,345,678"	12345678
Only digits are allowed after the decimal point.	"1.234 "	1.234
Use `E` or `e` for exponents. After the `e`, digits and a leading sign indicator are allowed.	" 123.45e-1"	12.345
If the integer part is not empty, then it must contain at least one digit.	" 0,.12 -"	-0.12
If the string contains a decimal point, then it must contain at least one digit.	" .1"	0.1
The string cannot contain more than one sign.	" 0.5 +"	0.5

Return Data Type

NUMERIC

Examples

This example shows an input with spaces before, after, and between the sign and the number:

SELECT PARSE_NUMERIC("  -  12.34 ") as parsed;

/*--------*
 | parsed |
 +--------+
 | -12.34 |
 *--------*/

This example shows an input with an exponent as well as the sign after the number:

SELECT PARSE_NUMERIC("12.34e-1-") as parsed;

/*--------*
 | parsed |
 +--------+
 | -1.234 |
 *--------*/

This example shows an input with multiple commas in the integer part of the number:

SELECT PARSE_NUMERIC("  1,2,,3,.45 + ") as parsed;

/*--------*
 | parsed |
 +--------+
 | 123.45 |
 *--------*/

This example shows an input with a decimal point and no digits in the whole number part:

SELECT PARSE_NUMERIC(".1234  ") as parsed;

/*--------*
 | parsed |
 +--------+
 | 0.1234 |
 *--------*/

Examples of invalid inputs

This example is invalid because the whole number part contains no digits:

SELECT PARSE_NUMERIC(",,,.1234  ") as parsed;

This example is invalid because there are whitespaces between digits:

SELECT PARSE_NUMERIC("1  23.4 5  ") as parsed;

This example is invalid because the number is empty except for an exponent:

SELECT PARSE_NUMERIC("  e1 ") as parsed;

This example is invalid because the string contains multiple signs:

SELECT PARSE_NUMERIC("  - 12.3 - ") as parsed;

This example is invalid because the value of the number falls outside the range of BIGNUMERIC:

SELECT PARSE_NUMERIC("12.34E100 ") as parsed;

This example is invalid because the string contains invalid characters:

SELECT PARSE_NUMERIC("$12.34") as parsed;

`SAFE_CAST`

SAFE_CAST(expression AS typename [format_clause])

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 replaces runtime errors with NULLs. However, during static analysis, impossible casts between two non-castable types still produce an error because the query is invalid.

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

/*--------------*
 | not_a_number |
 +--------------+
 | NULL         |
 *--------------*/

The structure of the format clause is unique to each type of cast and more information is available in the section for that cast.

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.