ALTER TABLE

The ALTER TABLE statement applies a schema change to a table.

Note:

This statement performs a schema change. For more information about how online schema changes work in CockroachDB, see Online Schema Changes.

Viewing schema changes

This schema change statement is registered as a job. You can view long-running jobs with SHOW JOBS.

For information on using ALTER TABLE, see the documents for its relevant subcommands.

Tip:

New in v19.1: Some subcommands can be used in combination in a single ALTER TABLE statement. For example, you can atomically rename a column and add a new column with the old name of the existing column.

Subcommand	Description	Can combine with other subcommands?
`ADD COLUMN`	Add columns to tables.	Yes
`ADD CONSTRAINT`	Add constraints to columns.	Yes
`ALTER COLUMN`	Change or drop a column's `DEFAULT` constraint or drop the `NOT NULL` constraint.	Yes
`ALTER TYPE`	Change a column's data type.	Yes
`CONFIGURE ZONE`	Configure replication zones for a table.	No
`DROP COLUMN`	Remove columns from tables.	Yes
`DROP CONSTRAINT`	Remove constraints from columns.	Yes
`EXPERIMENTAL_AUDIT`	Enable per-table audit logs.	Yes
`PARTITION BY`	Repartition or unpartition a table with partitions (Enterprise-only).	Yes
`RENAME COLUMN`	Change the names of columns.	Yes
`RENAME CONSTRAINT`	Change constraints columns.	Yes
`RENAME TABLE`	Change the names of tables.	No
`SPLIT AT`	Force a key-value layer range split at the specified row in the table.	No
`VALIDATE CONSTRAINT`	Check whether values in a column match a constraint on the column.	Yes

This schema change statement is registered as a job. You can view long-running jobs with SHOW JOBS.

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