|Subject||Re: [firebird-support] Indexes on subquery|
> From: Svein Erling TysværBut it does not make much sense to use "UNION" instead of "UNION ALL"
> Having said all that, I was somewhat surprised about one query I issued yesterday:
> SELECT max(MyField) FROM TableA
> SELECT max(MyField) FROM TableB
> used my descending indexes on MyField. However:
> SELECT 'TableA' as TableName, max(MyField) FROM TableA group by 1
> SELECT 'TableB', max(MyField) FROM TableB group by 1
> used NATURAL for both tables ...
in this particular query :)