| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | "Booth, Robert" <Robert_Booth(at)intuit(dot)com> |
| Cc: | "PostgreSQL General" <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: Update FROM clause? |
| Date: | 2002-11-01 20:18:59 |
| Message-ID: | 1197.1036181939@sss.pgh.pa.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-general |
"Booth, Robert" <Robert_Booth(at)intuit(dot)com> writes:
> SELECT count(*)
> FROM (allforms LEFT OUTER JOIN aanda ON allforms.file__no =
> aanda.file__no)
> INNER JOIN formsin ON allforms.file__no = formsin.file__no
> WHERE ... Omitted ...
> The Postgres UPDATE Query:
> UPDATE allforms
> SET status = 'Okay to Edit'
> FROM formsin LEFT OUTER JOIN aanda ON formsin.file__no = aanda.file__no
> WHERE allforms.file__no = formsin.file__no
> AND ... Omitted, matches the Access Query ...
Those are not the same thing at all. Your UPDATE is more like
SELECT ...
FROM allforms,
(formsin LEFT OUTER JOIN aanda ON formsin.file__no = aanda.file__no)
WHERE allforms.file__no = formsin.file__no
AND ... Omitted, matches the Access Query ...
which is reversing the order of the inner and outer join steps.
Depending on your data this might yield quite a different result.
regards, tom lane
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Doug McNaught | 2002-11-01 20:22:43 | Re: [Q] Sequences, last_value and inserts |
| Previous Message | Bruno Wolff III | 2002-11-01 20:02:43 | Re: [Q] Sequences, last_value and inserts |