COMMENT ON

Use COMMENT ON to:

• Add a comment to an object.
• Update the comment to an object.
• Remove the comment from an object.

Syntax

{{% include-syntax file="examples/comment_on" example="syntax" %}}

Details

COMMENT ON stores a comment about an object in the database. Each object can only have one comment associated with it, so successive calls of COMMENT ON to a single object will overwrite the previous comment.

To read the comment on an object you need to query the mz_internal.mz_comments catalog table.

Privileges

The privileges required to execute this statement are:

{{% include-headless "/headless/sql-command-privileges/comment-on" %}}

For more information on ownership and privileges, see Role-based access control.

Examples

--- Add comments.
COMMENT ON TABLE foo IS 'this table is important';
COMMENT ON COLUMN foo.x IS 'holds all of the important data';

--- Update a comment.
COMMENT ON TABLE foo IS 'holds non-important data';

--- Remove a comment.
COMMENT ON TABLE foo IS NULL;

--- Read comments.
SELECT * FROM mz_internal.mz_comments;