| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Scott Marlowe <smarlowe(at)g2switchworks(dot)com> |
| Cc: | Greg Stark <gsstark(at)mit(dot)edu>, Stephan Szabo <sszabo(at)megazone(dot)bigpanda(dot)com>, Rick Schumeyer <rschumeyer(at)ieee(dot)org>, pgsql-sql(at)postgresql(dot)org |
| Subject: | Re: pg, mysql comparison with "group by" clause |
| Date: | 2005-10-13 18:49:37 |
| Message-ID: | 24789.1129229377@sss.pgh.pa.us |
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| Thread: | |
| Lists: | pgsql-sql |
>>>> In standard SQL you have to
>>>> write GROUP BY ... and list every single column you need from the master
>>>> table.
This thread seems to have gone off on a tangent that depends on the
assumption that the above is a correct statement. It's not. It *was*
true, in SQL92, but SQL99 lets you omit unnecessary GROUP BY columns.
The gripe against mysql, I think, is that they don't enforce the
conditions that guarantee the query will give a unique result.
The gripe against postgres is that we haven't implemented the SQL99
semantics yet.
regards, tom lane
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