The Oracle COMMENT statement add a comment about a table, view, materialized view, or column into the data dictionary.
The general format is:
COMMENT ON TABLE [schema.]tablename IS 'my comment';
COMMENT ON TABLE [schema.]viewname IS 'my comment';
COMMENT ON TABLE [schema.]materialized IS 'my comment';
COMMENT ON COLUMN [schema.]tablename.columnname IS 'my comment';
COMMENT ON COLUMN [schema.]viewname.columnname IS 'my comment';
COMMENT ON COLUMN [schema.]materialized.columnname IS 'my comment';
Example 1:
COMMENT ON TABLE invoice IS 'Invoice table';
COMMENT ON COLUMN invoice.detailname IS 'Product detail';
Example 2, delete comment:
COMMENT ON TABLE invoice IS '';
COMMENT ON COLUMN invoice.detailname IS '';