The GoogleSQL data manipulation language (DML) lets you update, insert, and delete data in GoogleSQL tables.
For information about how to use DML statements, see Inserting, updating, and deleting data using Data Manipulation Language. You can also modify data using mutations.
Tables used in examples
CREATE TABLE Singers (
SingerId INT64 NOT NULL,
FirstName STRING(1024),
LastName STRING(1024),
BirthDate DATE,
Status STRING(1024),
LastUpdated TIMESTAMP,
SingerInfo googlesql.example.SingerInfo,
AlbumInfo googlesql.example.Album,
) PRIMARY KEY(SingerId);
CREATE TABLE AlbumInfo (
SingerId INT64 NOT NULL,
AlbumId INT64 NOT NULL,
AlbumTitle STRING(MAX),
MarketingBudget INT64,
) PRIMARY KEY(SingerId, AlbumId),
INTERLEAVE IN PARENT Singers ON DELETE CASCADE;
CREATE TABLE Songs (
SingerId INT64 NOT NULL,
AlbumId INT64 NOT NULL,
TrackId INT64 NOT NULL,
SongName STRING(MAX),
Duration INT64,
SongGenre STRING(25),
) PRIMARY KEY(SingerId, AlbumId, TrackId),
INTERLEAVE IN PARENT AlbumInfo ON DELETE CASCADE;
CREATE TABLE Concerts (
VenueId INT64 NOT NULL,
SingerId INT64 NOT NULL,
ConcertDate DATE NOT NULL,
BeginTime TIMESTAMP,
EndTime TIMESTAMP,
TicketPrices ARRAY<INT64>,
) PRIMARY KEY(VenueId, SingerId, ConcertDate);
CREATE TABLE AckworthSingers (
SingerId INT64 NOT NULL,
FirstName STRING(1024),
LastName STRING(1024),
BirthDate DATE,
) PRIMARY KEY(SingerId);
CREATE TABLE Fans (
FanId STRING(36) DEFAULT (GENERATE_UUID()),
FirstName STRING(1024),
LastName STRING(1024),
) PRIMARY KEY(FanId);
Definitions for protocol buffers used in examples
pckage googlesql.example;
message SingerInfo {
optional string nationality = 1;
repeated Residence residence = 2;
message Residence {
required int64 start_year = 1;
optional int64 end_year = 2;
optional string city = 3;
optional string country = 4;
}
}
message Album {
optional string title = 1;
optional int64 tracks = 2;
repeated string comments = 3;
repeated Song song = 4;
message Song {
optional string songtitle = 1;
optional int64 length = 2;
repeated Chart chart = 3;
message Chart {
optional string chartname = 1;
optional int64 rank = 2;
}
}
}
Notation used in the syntax
- Square brackets
[ ]
indicate optional clauses. - Parentheses
( )
indicate literal parentheses. - The vertical bar
|
indicates a logical OR. - Curly braces
{ }
enclose a set of options. - A comma followed by an ellipsis indicates that the preceding item can repeat
in a comma-separated list.
item [, ...]
indicates one or more items, and[item, ...]
indicates zero or more items. - A comma
,
indicates the literal comma. - Angle brackets
<>
indicate literal angle brackets. - A colon
:
indicates a definition. - Uppercase words, such as
INSERT
, are keywords.
INSERT statement
Use the INSERT
statement to add new rows to a table. The INSERT
statement
can insert one or more rows specified by value expressions, or zero or more rows
produced by a query. The statement by default returns the number of rows
inserted into the table.
INSERT [[OR] IGNORE | UPDATE]
[INTO] table_name
(column_name_1 [, ..., column_name_n] )
input [return_clause]
input:
VALUES (row_1_column_1_expr [, ..., row_1_column_n_expr ] )
[, ..., (row_k_column_1_expr [, ..., row_k_column_n_expr ] ) ]
| select_query
expr: value_expression | DEFAULT
return_clause:
THEN RETURN [ WITH ACTION [ AS alias ] ] { select_all | expression [ [ AS ] alias ] } [, ...]
select_all:
[ table_name. ]*
[ EXCEPT ( column_name [, ...] ) ]
[ REPLACE ( expression [ AS ] column_name [, ...] ) ]
INSERT
statements must comply with these rules:
- The column names can be in any order.
- Duplicate names are not allowed in the list of columns.
- The number of columns must match the number of values.
- GoogleSQL matches the values in the
VALUES
clause or the select query positionally with the column list. - Each value must be type compatible with its associated column.
- The values must comply with any constraints in the schema, for example, unique secondary indexes.
- All non-null columns must appear in the column list, and have a non-null value specified.
If a statement does not comply with the rules, Spanner raises an error and the entire statement fails.
If the statement attempts to insert a duplicate row, as determined by the primary key, then the entire statement fails.
Value type compatibility
Values that you add in an INSERT
statement must be compatible with the target
column's type. A value's type is compatible with the target column's type if the
value meets one of the following criteria:
- The value type matches the column type exactly. For example, inserting a
value of type
INT64
in a column that has a type ofINT64
is compatible. - GoogleSQL can implicitly coerce the value into the target type.
Default values
Use the DEFAULT
keyword to insert the default value of a column.
If a column is not included in the list, GoogleSQL assigns the default
value of the column. If the column has no defined
default value, NULL
is assigned to the column.
The use of default values is subject to current Spanner limits,
including the mutation limit. If a column has a default value and it is used in
an insert or update, the column is counted as one mutation. For example,
assuming that table T
has three columns and that col_a
has a default value,
the following inserts each result in three mutations:
INSERT INTO T (id, col_a, col_b) VALUES (1, DEFAULT, 1);
INSERT INTO T (id, col_a, col_b) VALUES (2, 200, 2);
INSERT INTO T (id, col_b) VALUES (3, 3);
For more information about default column values, see the
DEFAULT ( expression )
clause in CREATE TABLE
.
For more information about mutations, see What are mutations?.
INSERT OR IGNORE
Use the INSERT OR IGNORE
clause to insert new rows that don't
exist in the table. If the primary key of the row already exists, then the row
is ignored. For an INSERT OR IGNORE
query that inserts multiple rows or
inserts from a subquery, only the new rows are inserted. Rows where the primary
key already exists are ignored.
For example, if the primary key is SingerId
and the table already contains
a SingerId
of 7, then in the following example, INSERT
would insert the
first row and ignore the second row:
INSERT OR IGNORE INTO Singers
(SingerId, FirstName, LastName, Birthdate, Status, SingerInfo)
VALUES (5, "Zak", "Sterling", "1996-03-12", "active", "nationality:'USA'"),
(7, "Edie", "Silver", "1998-01-23", "active", "nationality:'USA'");
You can use INSERT OR IGNORE
in single or batch DML requests using the
executeBatchDml
API.
INSERT OR UPDATE
Use the INSERT OR UPDATE
clause to insert or update a row. If
the primary key is not found, a new row is inserted. If a row with the primary
key already exists in the table, then it is updated with the values that you
specify in the statement.
For example, in the following statement, INSERT OR UPDATE
modifies the column
value of Status
from active
to inactive
in the existing table with the
primary key SingerId
of 5
.
INSERT OR UPDATE INTO Singers
(SingerId, Status)
VALUES (5, "inactive");
If the row does not exist, the previous statement inserts a new row with values in the specified fields.
You can use INSERT OR UPDATE
in single or batch DML requests using the
executeBatchDml
API.
THEN RETURN
Use the THEN RETURN
clause to return the results of the INSERT
operation and
selected data from the newly inserted rows. This clause is especially useful for
retrieving values of columns with default values, generated columns, and
auto-generated keys, without having to use additional SELECT
statements.
Use the THEN RETURN
clause to capture expressions based on newly inserted rows
that include the following:
WITH ACTION
: An optional clause that adds a string column calledACTION
to the result row set. Each value in this column represents the type of action that was applied to the column during statement execution. Values includeINSERT
,DELETE
, andUPDATE
. TheACTION
column is appended as the last output column.*
: Returns all columns.table_name.*
: Returns all columns from the table. You cannot use the .* expression with other expressions, including field access.EXCEPT ( column_name [, ...] )
: Specifies the columns to exclude from the result. All matching column names are omitted from the output.REPLACE ( expression [ AS ] column_name [, ...] )
: Specifies one or moreexpression AS identifier
clauses. Each identifier must match a column name from thetable_name.*
statement. In the output column list, the column that matches the identifier in aREPLACE
clause is replaced by the expression in thatREPLACE
clause. Note that the value that gets inserted into the table is not replaced, just the value returned by theTHEN RETURN
clause.expression
: Represents a column name of the table specified bytable_name
or an expression that uses any combination of such column names. Column names are valid if they belong to columns of thetable_name
. Excluded expressions include aggregate and analytic functions.alias
: Represents a temporary name for an expression in the query.
For instructions and code samples, see Modify data with the returning DML statements.
INSERT examples
INSERT using literal values examples
The following example adds two rows to the Singers
table.
INSERT INTO Singers (SingerId, FirstName, LastName, SingerInfo)
VALUES(1, 'Marc', 'Richards', "nationality: 'USA'"),
(2, 'Catalina', 'Smith', "nationality: 'Brazil'"),
(3, "Andrew", "Duneskipper", NULL);
These are the two new rows in the table:
SingerId | FirstName | LastName | BirthDate | Status | SingerInfo | AlbumInfo |
---|---|---|---|---|---|---|
1 | Marc | Richards | NULL | NULL | nationality: USA | NULL |
2 | Catalina | Smith | NULL | NULL | nationality: Brazil | NULL |
3 | Alice | Trentor | NULL | NULL | NULL | NULL |
INSERT using a SELECT statement example
The following example shows how to copy the data from one table into another
table using a SELECT
statement as the input:
INSERT INTO Singers (SingerId, FirstName, LastName)
SELECT SingerId, FirstName, LastName
FROM AckworthSingers;
If the Singers
table had no rows, and the AckworthSingers
table had three
rows, then there are now three rows in the Singers
table:
SingerId | FirstName | LastName | BirthDate | Status | SingerInfo | AlbumInfo |
---|---|---|---|---|---|---|
1 | Marc | Richards | NULL | NULL | NULL | NULL |
2 | Catalina | Smith | NULL | NULL | NULL | NULL |
3 | Alice | Trentor | NULL | NULL | NULL | NULL |
The following example shows how to use UNNEST
to return a table that is the
input to the INSERT
command.
INSERT INTO Singers (SingerId, FirstName, LastName)
SELECT *
FROM UNNEST ([(4, 'Lea', 'Martin'),
(5, 'David', 'Lomond'),
(6, 'Elena', 'Campbell')]);
After adding these three additional rows to the table from the previous example,
there are six rows in the Singers
table:
SingerId | FirstName | LastName | BirthDate | Status | SingerInfo | AlbumInfo |
---|---|---|---|---|---|---|
1 | Marc | Richards | NULL | NULL | NULL | NULL |
2 | Catalina | Smith | NULL | NULL | NULL | NULL |
3 | Alice | Trentor | NULL | NULL | NULL | NULL |
4 | Lea | Martin | NULL | NULL | NULL | NULL |
5 | David | Lomond | NULL | NULL | NULL | NULL |
6 | Elena | Campbell | NULL | NULL | NULL | NULL |
INSERT using a subquery example
The following example shows how to insert a row into a table, where one of the values is computed using a subquery:
INSERT INTO Singers (SingerId, FirstName)
VALUES (4, (SELECT FirstName FROM AckworthSingers WHERE SingerId = 4));
The following tables show the data before the statement is executed.
Singers
SingerId | FirstName | LastName | BirthDate | Status | SingerInfo | AlbumInfo |
---|---|---|---|---|---|---|
1 | Marc | Richards | NULL | NULL | NULL | NULL |
2 | Catalina | Smith | NULL | NULL | NULL | NULL |
AckworthSingers
SingerId | FirstName | LastName | BirthDate |
---|---|---|---|
4 | Lea | Martin | NULL |
5 | David | Lomond | NULL |
The following table shows the data after the statement is executed.
Singers
SingerId | FirstName | LastName | BirthDate | Status | SingerInfo | AlbumInfo |
---|---|---|---|---|---|---|
1 | Marc | Richards | NULL | NULL | NULL | NULL |
2 | Catalina | Smith | NULL | NULL | NULL | NULL |
4 | Lea | NULL | NULL | NULL | NULL | NULL |
To include multiple columns, you include multiple subqueries:
INSERT INTO Singers (SingerId, FirstName, LastName)
VALUES (4,
(SELECT FirstName FROM AckworthSingers WHERE SingerId = 4),
(SELECT LastName FROM AckworthSingers WHERE SingerId = 4));
INSERT with THEN RETURN examples
The following query inserts two rows into a table, uses THEN RETURN
to fetch
the SingerId column from these rows, and computes a new column called
FullName
.
INSERT INTO Singers (SingerId, FirstName, LastName)
VALUES
(7, 'Melissa', 'Garcia'),
(8, 'Russell', 'Morales')
THEN RETURN SingerId, FirstName || ' ' || LastName AS FullName;
The following table shows the query result:
SingerId | FullName |
---|---|
7 | Melissa Garcia |
8 | Russell Morales |
The following query inserts a row to the Fans
table. Spanner
automatically generates a Version 4 UUID for the primary key FanId
, and
returns it using the THEN RETURN
clause.
INSERT INTO Fans (FirstName, LastName)
VALUES ('Melissa', 'Garcia')
THEN RETURN FanId;
The following table shows the query result:
FanId |
---|
6af91072-f009-4c15-8c42-ebe38ae83751 |
The following query tries to insert or update a row into a table. It uses
THEN RETURN
to fetch the modified row and WITH ACTION
to show the modified
row action type.
INSERT OR UPDATE Singers (SingerId, FirstName, LastName)
VALUES (7, 'Melissa', 'Gartner')
THEN RETURN WITH ACTION SingerId, FirstName || ' ' || LastName AS FullName;
SingerId | FullName | Action |
---|---|---|
7 | Melissa Gartner | UPDATE |
INSERT OR IGNORE example
The following query inserts a row in the Singers
table for singers with an ID
between 10 and 100. If an ID already exists in Singers
, it's
ignored.
INSERT OR IGNORE INTO Singers (
SingerId, FirstName, LastName, BirthDate, Status, SingerInfo)
(SELECT id, fname, lname, dob, status, info
FROM latest_album
WHERE id > 10
AND id < 100);
DELETE statement
Use the DELETE
statement to delete rows from a table.
[statement_hint_expr] DELETE [FROM] table_name [table_hint_expr] [[AS] alias] WHERE condition [return_clause];
statement_hint_expr: '@{' statement_hint_key = statement_hint_value '}'
table_hint_expr: '@{' table_hint_key = table_hint_value '}'
return_clause:
THEN RETURN [ WITH ACTION [ AS alias ] ] { select_all | expression [ [ AS ] alias ] } [, ...]
select_all:
[ table_name. ]*
[ EXCEPT ( column_name [, ...] ) ]
[ REPLACE ( expression [ AS ] column_name [, ...] ) ]
WHERE clause
The WHERE
clause is required. This requirement can help prevent accidentally
deleting all the rows in a table. To delete all rows in a table, set the
condition
to true
:
DELETE FROM table_name WHERE true;
The WHERE
clause can contain any valid SQL statement, including a subquery
that refers to other tables.
Aliases
The WHERE
clause has an implicit alias to table_name
. This alias lets you
reference columns in table_name
without qualifying them with
table_name
. For example, if your statement started with DELETE FROM
Singers
, then you could access any columns of Singers
in the WHERE
clause.
In this example, FirstName
is a column in the Singers
table:
DELETE FROM Singers WHERE FirstName = 'Alice';
You can also create an explicit alias using the optional AS
keyword. For more
details on aliases, see Query syntax.
THEN RETURN
With the optional THEN RETURN
clause, you can obtain data from rows that are
being deleted in a table. To learn more about the values that you can use in
this clause, see THEN RETURN.
Statement hints
statement_hint_expr
is a statement-level hint. The following hints are
supported:
statement_hint_key |
statement_hint_value |
Description |
---|---|---|
PDML_MAX_PARALLELISM | An integer between 1 to 1000 | Sets the maximum parallelism for Partitioned DML queries. This hint is only valid with Partitioned DML query execution mode. |
Table hints
table_hint_expr
is a hint for accessing the table. The following hints are
supported:
table_hint_key |
table_hint_value |
Description |
---|---|---|
FORCE_INDEX | Index name | Use specified index when querying rows to be deleted. |
FORCE_INDEX | _BASE_TABLE | Don't use an index. Instead, scan the base table. |
DELETE examples
DELETE with WHERE clause example
The following DELETE
statement deletes all singers whose first name is
Alice
.
DELETE FROM Singers WHERE FirstName = 'Alice';
The following table shows the data before the statement is executed.
SingerId | FirstName | LastName | BirthDate | Status | SingerInfo | AlbumInfo |
---|---|---|---|---|---|---|
1 | Marc | Richards | NULL | NULL | NULL | NULL |
2 | Catalina | Smith | NULL | NULL | NULL | NULL |
3 | Alice | Trentor | NULL | NULL | NULL | NULL |
The following table shows the data after the statement is executed.
SingerId | FirstName | LastName | BirthDate | Status | SingerInfo | AlbumInfo |
---|---|---|---|---|---|---|
1 | Marc | Richards | NULL | NULL | NULL | NULL |
2 | Catalina | Smith | NULL | NULL | NULL | NULL |
DELETE with subquery example
The following statement deletes any singer in SINGERS
whose first name is
not in AckworthSingers
.
DELETE FROM Singers
WHERE FirstName NOT IN (SELECT FirstName from AckworthSingers);
The following table shows the data before the statement is executed.
Singers
SingerId | FirstName | LastName | BirthDate | Status | SingerInfo | AlbumInfo |
---|---|---|---|---|---|---|
1 | Marc | Richards | NULL | NULL | NULL | NULL |
2 | Catalina | Smith | NULL | NULL | NULL | NULL |
3 | Alice | Trentor | NULL | NULL | NULL | NULL |
4 | Lea | Martin | NULL | NULL | NULL | NULL |
5 | David | Lomond | NULL | NULL | NULL | NULL |
6 | Elena | Campbell | NULL | NULL | NULL | NULL |
AckworthSingers
SingerId | FirstName | LastName | BirthDate |
---|---|---|---|
4 | Lea | Martin | NULL |
5 | David | Lomond | NULL |
6 | Elena | Campbell | NULL |
The following table shows the data after the statement is executed.
Singers
SingerId | FirstName | LastName | BirthDate | Status | SingerInfo | AlbumInfo |
---|---|---|---|---|---|---|
4 | Lea | Martin | NULL | NULL | NULL | NULL |
5 | David | Lomond | NULL | NULL | NULL | NULL |
6 | Elena | Campbell | NULL | NULL | NULL | NULL |
DELETE with THEN RETURN example
The following query deletes all rows in a table that
contains a singer called Melissa
and returns all columns in the deleted rows
except the LastUpdated
column.
DELETE FROM Singers WHERE Firstname = 'Melissa'
THEN RETURN * EXCEPT (LastUpdated);
The following table shows the query result:
SingerId | FirstName | LastName | BirthDate |
---|---|---|---|
7 | Melissa | Garcia | NULL |
UPDATE statement
Use the UPDATE
statement to update existing rows in a table.
[statement_hint_expr] UPDATE table_name [table_hint_expr] [[AS] alias]
SET update_item [, ...]
WHERE condition [return_clause];
update_item: column_name = { expression | DEFAULT }
statement_hint_expr: '@{' statement_hint_key = statement_hint_value '}'
table_hint_expr: '@{' table_hint_key = table_hint_value '}'
return_clause:
THEN RETURN [ WITH ACTION [ AS alias ] ] { select_all | expression [ [ AS ] alias ] } [, ...]
select_all:
[ table_name. ]*
[ EXCEPT ( column_name [, ...] ) ]
[ REPLACE ( expression [ AS ] column_name [, ...] ) ]
Where:
table_name
is the name of a table to update.- The
SET
clause is a list of update_items to perform on each row where theWHERE
condition is true. expression
is an update expression. The expression can be a literal, a SQL expression, or a SQL subquery.statement_hint_expr
is a statement-level hint. The following hints are supported:statement_hint_key
statement_hint_value
Description PDML_MAX_PARALLELISM An integer between 1 to 1000 Sets the maximum parallelism for Partitioned DML queries.
This hint is only valid with Partitioned DML query execution mode.table_hint_expr
is a hint for accessing the table. The following hints are supported:table_hint_key
table_hint_value
Description FORCE_INDEX Index name Use specified index when querying rows to be updated. FORCE_INDEX _BASE_TABLE Don't use an index. Instead, scan the base table.
UPDATE
statements must comply with the following rules:
- A column can appear only once in the
SET
clause. - The columns in the
SET
clause can be listed in any order. - Each value must be type compatible with its associated column.
- The values must comply with any constraints in the schema, such as unique secondary indexes or non-nullable columns.
- Updates with joins are not supported.
- You cannot update primary key columns.
If a statement does not comply with the rules, Spanner raises an error and the entire statement fails.
Columns not included in the SET
clause are not modified.
Column updates are performed simultaneously. For example, you can swap two
column values using a single SET
clause:
SET x = y, y = x
Value type compatibility
Values updated with an UPDATE
statement must be compatible with the target
column's type. A value's type is compatible with the target column's type if the
value meets one of the following criteria:
- The value type matches the column type exactly. For example, the value type
is
INT64
and the column type isINT64
. - GoogleSQL can implicitly coerce the value into the target type.
Default values
The DEFAULT
keyword sets the value of a column to its default value. If the
column has no defined default value, the DEFAULT
keyword sets it to NULL
.
The use of default values is subject to current Spanner limits, including the mutation limit. If a column has a default value and it is used in an insert or update, the column is counted as one mutation. For example, assume that in table T
, col_a
has a default value. The following updates each result in two mutations. One comes from the primary key, and another comes from either the explicit value (1000) or the default value.
UPDATE T SET col_a = 1000 WHERE id=1;
UPDATE T SET col_a = DEFAULT WHERE id=3;
For more information about default column values, see the
DEFAULT ( expression )
clause in CREATE TABLE
.
For more information about mutations, see What are mutations?.
WHERE clause
The WHERE
clause is required. This requirement can help prevent accidentally
updating all the rows in a table. To update all rows in a table, set the
condition
to true
.
The WHERE
clause can contain any valid SQL boolean expression, including a
subquery that refers to other tables.
THEN RETURN
With the optional THEN RETURN
clause, you can obtain data from rows that are
being updated in a table. To learn more about the values that you can use in
this clause, see THEN RETURN.
Aliases
The WHERE
clause has an implicit alias to table_name
. This alias lets you
reference columns in table_name
without qualifying them with
table_name
. For example, if your statement starts with UPDATE Singers
, then
you can access any columns of Singers
in the WHERE
clause. In this example,
FirstName
and LastName
are columns in the Singers
table:
UPDATE Singers
SET BirthDate = '1990-10-10'
WHERE FirstName = 'Marc' AND LastName = 'Richards';
You can also create an explicit alias using the optional AS
keyword. For more
details on aliases, see Query syntax.
UPDATE examples
UPDATE with literal values example
The following example updates the Singers
table by updating the BirthDate
column in one of the rows.
UPDATE Singers
SET BirthDate = '1990-10-10', SingerInfo = "nationality:'USA'"
WHERE FirstName = 'Marc' AND LastName = 'Richards';
The following table shows the data before the statement is executed.
SingerId | FirstName | LastName | BirthDate | Status | SingerInfo | AlbumInfo |
---|---|---|---|---|---|---|
1 | Marc | Richards | NULL | NULL | NULL | NULL |
2 | Catalina | Smith | NULL | NULL | NULL | NULL |
3 | Alice | Trentor | NULL | NULL | NULL | NULL |
The following table shows the data after the statement is executed.
SingerId | FirstName | LastName | BirthDate | Status | SingerInfo | AlbumInfo |
---|---|---|---|---|---|---|
1 | Marc | Richards | 1990-10-10 | NULL | nationality: USA | NULL |
2 | Catalina | Smith | NULL | NULL | NULL | NULL |
3 | Alice | Trentor | NULL | NULL | NULL | NULL |
UPDATE ARRAY columns example
The following example updates an ARRAY
column.
UPDATE Concerts SET TicketPrices = [25, 50, 100] WHERE VenueId = 1;
The following table shows the data before the statement is executed.
VenueId | SingerId | ConcertDate | BeginTime | EndTime | TicketPrices |
---|---|---|---|---|---|
1 | 1 | NULL | NULL | NULL | NULL |
1 | 2 | NULL | NULL | NULL | NULL |
2 | 3 | NULL | NULL | NULL | NULL |
The following table shows the data after the statement is executed.
VenueId | SingerId | ConcertDate | BeginTime | EndTime | TicketPrices |
---|---|---|---|---|---|
1 | 1 | 2018-01-01 | NULL | NULL | [25, 50, 100] |
1 | 2 | 2018-01-01 | NULL | NULL | [25, 50, 100] |
2 | 3 | 2018-01-01 | NULL | NULL | NULL |
UPDATE with THEN RETURN example
The following query updates all rows where the singer first name is equal to
Russell
and returns the SingerId
in the updated rows. It also extracts the
year from the updated BirthDate
column as a new output column called year
.
UPDATE Singers
SET BirthDate = '1990-10-10'
WHERE FirstName = 'Russell'
THEN RETURN SingerId, EXTRACT(YEAR FROM BirthDate) AS year;
The following table shows the query result:
SingerId | year |
---|---|
8 | 1990 |
Bound STRUCT parameters
You can use bound STRUCT
parameters
in the WHERE
clause of a DML statement. The following code example updates the
LastName
in rows filtered by FirstName
and LastName
.
C#
Go
Java
Node.js
PHP
Python
Ruby
Commit timestamps
Use the PENDING_COMMIT_TIMESTAMP
function to write commit timestamps to a TIMESTAMP
column. The column must
have the allow_commit_timestamp
option set to true
. The following DML
statement updates the LastUpdated
column in the Singers
table with the
commit timestamp:
UPDATE Singers SET LastUpdated = PENDING_COMMIT_TIMESTAMP() WHERE SingerId = 1;
For more information on using commit timestamps in DML, see Commit timestamps in GoogleSQL-dialect databases and Commit timestamps in PostgreSQL-dialect databases.
Update fields in protocol buffers
You can update non-repeating and repeating fields in protocol buffers.
Consider the Singers example table.
It contains a column, AlbumInfo
, of type Albums
, and the Albums
column
contains a non-repeating field tracks
.
The following statement updates the value of tracks
:
UPDATE Singers s
SET s.AlbumInfo.tracks = 15
WHERE s.SingerId = 5 AND s.Albums.title = "Fire is hot";
You can also update a repeated field using an array of values:
UPDATE Singers s
SET s.AlbumInfo.comments = ["A good album!", "Hurt my ears!", "Totally unlistenable."]
WHERE s.SingerId = 5 AND s.Albums.title = "Fire is Hot";
Nested updates
You can construct DML statements inside a parent update statement that modify a repeated field of a protocol buffer or an array. These statements are called nested updates.
For example, the Album
message contains a repeated field called comments
.
This nested update statement adds a comment to an album:
UPDATE Singers s
SET (INSERT s.AlbumInfo.comments
VALUES ("Groovy!"))
WHERE s.SingerId = 5 AND s.AlbumInfo.title = "Fire is Hot";
Album
also contains a repeated protocol buffer, Song
, which provides
information about a song on the album. This nested update statement updates the
album with a new song:
UPDATE Singers s
SET (INSERT s.AlbumInfo.Song(Song)
VALUES ("songtitle: 'Bonus Track', length: 180"))
WHERE s.SingerId = 5 AND s.AlbumInfo.title = "Fire is Hot";
If the repeated field is another protocol buffer, you can provide the protocol buffer as a string literal. For example, the following statement adds a new song to the album and updates the number of tracks.
UPDATE Singers s
SET (INSERT s.AlbumInfo.Song
VALUES ('''songtitle: 'Bonus Track', length:180''')),
s.Albums.tracks = 16
WHERE s.SingerId = 5 and s.AlbumInfo.title = "Fire is Hot";
You can also nest a nested update statement in another nested update statement.
For example, the Song
protocol buffer itself has another repeated
protocol buffer, Chart
, which provides information on what chart the song
appears on, and what rank it has.
The following statement adds a new chart to a song:
UPDATE Singers s
SET (UPDATE s.AlbumInfo.Song so
SET (INSERT INTO so.Chart
VALUES ("chartname: 'Galaxy Top 100', rank: 5"))
WHERE so.songtitle = "Bonus Track")
WHERE s.SingerId = 5;
This following statement updates the chart to reflect a new rank for the song:
UPDATE Singers s
SET (UPDATE s.AlbumInfo.Song so
SET (UPDATE so.Chart c
SET c.rank = 2
WHERE c.chartname = "Galaxy Top 100")
WHERE so.songtitle = "Bonus Track")
WHERE s.SingerId = 5;
GoogleSQL treats an array or repeated field inside a row that matches
an UPDATE WHERE
clause as a table, with individual elements of the array or
field treated like rows. These rows can then have nested DML statements run
against them, allowing you to delete, update, and insert data as needed.
Modify multiple fields
The previous sections demonstrates how to update a single value in a compound data type. You can also modify multiple fields in a compound data type within a single statement. For example:
UPDATE Singers s
SET
(DELETE FROM s.SingerInfo.Residence r WHERE r.City = 'Seattle'),
(UPDATE s.Albums.Song song SET song.songtitle = 'No, This Is Rubbish' WHERE song.songtitle = 'This Is Pretty Good'),
(INSERT s.Albums.Song VALUES ("songtitle: 'The Second Best Song'"))
WHERE SingerId = 3 AND s.Albums.title = 'Go! Go! Go!';
Nested queries are processed as follows:
- Delete all rows that match a
WHERE
clause of aDELETE
statement. - Update any remaining rows that match a
WHERE
clause of anUPDATE
statement. Each row must match at most oneUPDATE WHERE
clause, or the statement fails due to overlapping updates. - Insert all rows in
INSERT
statements.
You must construct nested statements that affect the same field in the following order:
DELETE
UPDATE
INSERT
For example:
UPDATE Singers s
SET
(DELETE FROM s.SingerInfo.Residence r WHERE r.City = 'Seattle'),
(UPDATE s.SingerInfo.Residence r SET r.end_year = 2015 WHERE r.City = 'Eugene'),
(INSERT s.Albums.Song VALUES ("songtitle: 'The Second Best Song'"))
WHERE SingerId = 3 AND s.Albums.title = 'Go! Go! Go!';
The following statement is invalid, because the UPDATE
statement
happens after the INSERT
statement.
UPDATE Singers s
SET
(DELETE FROM s.SingerInfo.Residence r WHERE r.City = 'Seattle'),
(INSERT s.Albums.Song VALUES ("songtitle: 'The Second Best Song'")),
(UPDATE s.SingerInfo.Residence r SET r.end_year = 2015 WHERE r.City = 'Eugene')
WHERE SingerId = 3 AND s.Albums.title = 'Go! Go! Go!';
In nested queries, you can't use INSERT OR REPLACE
statements. These types
of statements don't work because arrays and other compound data types don't
always have a primary key, so there is no applicable definition of duplicate
rows.