I have created a function that does not give any errors itself but when calling it I get an error. I know I technically don’t need a function but for my scenario I need to be using one.

The error:

QUERY “SELECT (show_date) FROM show” returned more than one row.
CONTEXT: PL/PGSql function change_data_type() line 3 at RETURN

CREATE OR REPLACE FUNCTION change_data_type()
RETURNS date as $$
BEGIN
    RETURN DATE(show_date) FROM show;
END;
$$ LANGUAGE PLPGSQL;

SELECT change_data_type;