| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Alexander Farber <alexander(dot)farber(at)gmail(dot)com> |
| Cc: | pgsql-general <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: WHERE ... IN condition and multiple columns in subquery |
| Date: | 2016-10-28 14:06:48 |
| Message-ID: | 14473.1477663608@sss.pgh.pa.us |
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| Thread: | |
| Lists: | pgsql-general |
Alexander Farber <alexander(dot)farber(at)gmail(dot)com> writes:
> is it please possible to rewrite the SQL query
> SELECT DISTINCT ON (uid)
> uid,
> female,
> given,
> photo,
> place
> FROM words_social
> WHERE uid IN (SELECT player1 FROM games)
> OR uid IN (SELECT player2 FROM games)
> ORDER BY uid, stamp DESC
You could do
WHERE uid IN (SELECT player1 FROM games UNION SELECT player2 FROM games)
(or possibly UNION ALL would be a trifle faster). This still reads the
"games" CTE twice; but since you're evaluating that CTE elsewhere in the
query, I think the additional follower node isn't worth trying to get
rid of.
regards, tom lane
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