From: | Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | The Hermit Hacker <scrappy(at)hub(dot)org>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: [HACKERS] Re: [GENERAL] Re: [PHP3] Re: PostgreSQL vs Mysql comparison |
Date: | 1999-10-05 15:50:13 |
Message-ID: | 199910051550.LAA13312@candle.pha.pa.us |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
> That's not a bug, it means what it says: HAVING clauses should contain
> aggregate functions. Otherwise they might as well be WHERE clauses.
> (In this example, flushing rows with negative a before the group step,
> rather than after, is obviously a win, not least because it would
> allow the use of an index on a.)
>
> However, I can't see anything in the SQL92 spec that requires you to
> use HAVING intelligently, so maybe this error should be downgraded to
> a notice? "HAVING with no aggregates would be faster as a WHERE"
> (but we'll do it anyway to satisfy pedants...)
If we allow them, then people can do things like:
HAVING max(a) > b
which seems strange. Would we handle that?
--
Bruce Momjian | http://www.op.net/~candle
maillist(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026
From | Date | Subject | |
---|---|---|---|
Next Message | Peter Eisentraut | 1999-10-05 18:12:29 | psql Week 1 |
Previous Message | Bruce Momjian | 1999-10-05 15:28:06 | Re: [HACKERS] How to add a new build-in operator |