UPDATE

UPDATE changes values stored in user-created tables.

Syntax

UPDATE <table_name> [ AS <table_alias> ]
   SET <column_name> = <expression> [, <column2_name> = <expression2>, ...]
[WHERE <condition(s)> ];

Details

Known limitations

• UPDATE cannot be used inside transactions.
• UPDATE can reference read-write tables but not sources or read-only tables.
• Low performance. While processing an UPDATE statement, Materialize cannot process other INSERT, UPDATE, or DELETE statements.

Privileges

The privileges required to execute this statement are:

• USAGE privileges on the schemas that all relations and types in the query are contained in.
• UPDATE privileges on the table being updated.
• SELECT privileges on all relations in the query.
  • NOTE: if any item is a view, then the view owner must also have the necessary privileges to execute the view definition. Even if the view owner is a superuser, they still must explicitly be granted the necessary privileges.
• USAGE privileges on all types used in the query.
• USAGE privileges on the active cluster.

Examples

All examples below will use the example_table table:

CREATE TABLE example_table (a int, b text);
INSERT INTO example_table VALUES (1, 'hello'), (2, 'goodbye');

To verify the initial state of the table, run the following SELECT statement:

SELECT * FROM example_table;

The SELECT statement above should return two rows:

 a |    b
---+---------
 1 | hello
 2 | goodbye

Update based on a condition

The following UPDATE example includes a WHERE clause to specify which rows to update:

UPDATE example_table
SET a = a + 2
WHERE b = 'hello';

Only one row should be updated, namely the row with b = 'hello'. To verify that the operation updated the a column only for that row, run the following SELECT statement:

SELECT * FROM example_table;

The returned results show that column a was updated only for the row with b = 'hello':

 a |    b
---+---------
 3 | hello         -- Previous value: 1
 2 | goodbye

Update all rows

The following UPDATE example updates all rows in the table to set a to 0 and b to aloha:

UPDATE example_table
SET a = 0, b = 'aloha';

To verify the results, run the following SELECT statement:

SELECT * FROM example_table;

The returned results show that all rows were updated:

 a |   b
---+-------
 0 | aloha
 0 | aloha

Related pages

• CREATE TABLE
• INSERT
• SELECT