The ALTER TABLE statement applies a schema change to a table.
Note:
To understand how CockroachDB changes schema elements without requiring table locking or other user-visible downtime, see Online Schema Changes in CockroachDB.For information on using ALTER TABLE, see the documents for its relevant subcommands.
| Subcommand | Description | 
|---|---|
ADD COLUMN | 
Add columns to tables. | 
ADD CONSTRAINT | 
Add constraints to columns. | 
ALTER COLUMN | 
Change a column's Default constraint or drop the Not Null constraint. | 
DROP COLUMN | 
Remove columns from tables. | 
DROP CONSTRAINT | 
Remove constraints from columns. | 
RENAME COLUMN | 
Change the names of columns. | 
RENAME TABLE | 
Change the names of tables. | 
SPLIT AT | 
(Documentation pending) Potentially improve performance by identifying ideal locations to split data in the key-value layer. |