Tom Lane wrote: > Bruce Momjian <bruce@xxxxxxxxxx> writes: > > Well, it can be an expression _if_ the expression _matches_ an existing > > UNION column. > > You're mistaken. It has to be *an output column name*. Not anything else. Yea, I was thinking of this: SELECT *, state IS NULL AS state_is_null FROM income_tax_rate_us UNION SELECT *, state IS NULL AS state_is_null FROM income_tax_rate_us ORDER BY state_is_null Here the column result is an expression, and you reference that. Updated wording: test=> select * from test union select * from test order by x is null; ERROR: A UNION/INTERSECT/EXCEPT ORDER BY cannot use expressions or functions, only result column names -- Bruce Momjian bruce@xxxxxxxxxx EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. +
