UPDATE

Synopsis

Use the UPDATE statement to update one or more column values for a row in table.

Syntax

Diagram

using_expression

using_expression = ttl_or_timestamp_expression { 'AND' ttl_or_timestamp_expression };

ttl_or_timestamp_expression

ttl_or_timestamp_expression = 'TTL' ttl_expression | 'TIMESTAMP' timestamp_expression;

update ::= UPDATE table_name [ USING using_expression ] SET assignment
           [ , ... ]  WHERE where_expression
           [ IF { if_expression
                  | [ NOT ] EXISTS
                  | if_expression OR [ NOT ] EXISTS } ]
           [ RETURNS STATUS AS ROW ]


assignment ::= { column_name | column_name'['index_expression']' } '=' expression

Where

• table_name is an identifier (possibly qualified with a keyspace name).
• Restrictions for ttl_expression, where_expression, and if_expression are covered in the Semantics section.
• See Expressions for more information on syntax rules.

Semantics

• An error is raised if the specified table_name does not exist.
• Update statement uses upsert semantics, meaning it inserts the row being updated if it does not already exists.
• The USING TIMESTAMP clause indicates you would like to perform the UPDATE as if it was done at the timestamp provided by the user. The timestamp is the number of microseconds since epoch.
• Note: You should either use the USING TIMESTAMP clause in all of your statements or none of them. Using a mix of statements where some have USING TIMESTAMP and others do not will lead to very confusing results.
• Updating rows USING TTL is not supported on tables with transactions enabled.
• You cannot update the columns in the primary key. As a workaround, you have to delete the row and insert a new row.
• UPDATE is always done at QUORUM consistency level irrespective of setting.

WHERE clause

• The where_expression and if_expression must evaluate to boolean values.
• The where_expression must specify conditions for all primary-key columns.
• The where_expression must not specify conditions for any regular columns.
• The where_expression can only apply AND and = operators. Other operators are not yet supported.

IF clause

• The if_expression can only apply to non-key columns (regular columns).
• The if_expression can contain any logical and boolean operators.

USING clause

• ttl_expression must be an integer value (or a bind variable marker for prepared statements).
• timestamp_expression must be an integer value (or a bind variable marker for prepared statements).

Examples

Update a value in a table

ycqlsh:example> CREATE TABLE employees(department_id INT,
                                      employee_id INT,
                                      name TEXT,
                                      age INT,
                                      PRIMARY KEY(department_id, employee_id));

ycqlsh:example> INSERT INTO employees(department_id, employee_id, name, age) VALUES (1, 1, 'John', 30);

Update the value of a non primary-key column.

ycqlsh:example> UPDATE employees SET name = 'Jack' WHERE department_id = 1 AND employee_id = 1;

Using upsert semantics to update a non-existent row (that is, insert the row).

ycqlsh:example> UPDATE employees SET name = 'Jane', age = 40 WHERE department_id = 1 AND employee_id = 2;

ycqlsh:example> SELECT * FROM employees;

 department_id | employee_id | name | age
---------------+-------------+------+-----
             1 |           1 | Jack |  30
             1 |           2 | Jane |  40

Conditional update using the IF clause

The supported expressions are allowed in the 'SET' assignment targets.

ycqlsh:example> UPDATE employees SET age = age + 1 WHERE department_id = 1 AND employee_id = 1 IF name = 'Jack';

 [applied]
-----------
      True

Using upsert semantics to add a row, age is not set so will be 'null'.

ycqlsh:example> UPDATE employees SET name = 'Joe' WHERE department_id = 2 AND employee_id = 1 IF NOT EXISTS;

 [applied]
-----------
      True

ycqlsh:example> SELECT * FROM employees;

 department_id | employee_id | name | age
---------------+-------------+------+------
             2 |           1 |  Joe | null
             1 |           1 | Jack |   31
             1 |           2 | Jane |   40

Update with expiration time using the USING TTL clause

The updated values will persist for the TTL duration.

ycqlsh:example> UPDATE employees USING TTL 10 SET age = 32 WHERE department_id = 1 AND employee_id = 1;

ycqlsh:example> SELECT * FROM employees WHERE department_id = 1 AND employee_id = 1;

 department_id | employee_id | name | age
---------------+-------------+------+------
             1 |           1 | Jack |   32

11 seconds after the update (value will have expired).

ycqlsh:example> SELECT * FROM employees WHERE department_id = 1 AND employee_id = 1;

 department_id | employee_id | name | age
---------------+-------------+------+------
             1 |           1 | Jack | null

Update row with the USING TIMESTAMP clause

You can do this as follows:

ycqlsh:foo> INSERT INTO employees(department_id, employee_id, name, age) VALUES (1, 4, 'Jeff', 20) USING TIMESTAMP 1000;

ycqlsh:foo> SELECT * FROM employees;

 department_id | employee_id | name | age
---------------+-------------+------+------
             1 |           1 | Jack | null
             1 |           2 | Jane |   40
             1 |           4 | Jeff |   20
             2 |           1 |  Joe | null

(4 rows)

Now update the employees table.

ycqlsh:foo> UPDATE employees USING TIMESTAMP 500 SET age = 30 WHERE department_id = 1 AND employee_id = 4;

Not applied since timestamp is lower than 1000.

ycqlsh:foo> SELECT * FROM employees;

 department_id | employee_id | name | age
---------------+-------------+------+------
             1 |           1 | Jack | null
             1 |           2 | Jane |   40
             1 |           4 | Jeff |   20
             2 |           1 |  Joe | null

(4 rows)

ycqlsh:foo> UPDATE employees USING TIMESTAMP 1500 SET age = 30 WHERE department_id = 1 AND employee_id = 4;

Applied since timestamp is higher than 1000.

ycqlsh:foo> SELECT * FROM employees;

 department_id | employee_id | name | age
---------------+-------------+------+------
             1 |           1 | Jack | null
             1 |           2 | Jane |   40
             1 |           4 | Jeff |   30
             2 |           1 |  Joe | null

(4 rows)

RETURNS STATUS AS ROW

When executing a batch in YCQL, the protocol returns only one error or return status. The RETURNS STATUS AS ROW feature addresses this limitation and adds a status row for each statement.

See examples in batch docs.

See also

• CREATE TABLE
• DELETE
• INSERT
• SELECT
• Expression