| From: | Geoff Winkless <pgsqladmin(at)geoff(dot)dj> |
|---|---|
| To: | Alexander Farber <alexander(dot)farber(at)gmail(dot)com>, Postgres General <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: WHERE ... IN condition and multiple columns in subquery |
| Date: | 2016-10-28 14:31:58 |
| Message-ID: | CAEzk6feSkerworOgr4e2tVdJ7M9uGKJWBQ4rWGeCBGqP7+7y6Q@mail.gmail.com |
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| Lists: | pgsql-general |
On 28 October 2016 at 12:03, Alexander Farber <alexander(dot)farber(at)gmail(dot)com>
wrote:
> 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
>
> where first column player1 is fetched in a subquery and then column
> player2 is fetched from the same table?
>
You could use
WHERE EXISTS (SELECT FROM games WHERE player1=uid OR player2=uid)
although as Tom says, it's dubious whether that will result in a
significant speedup.
Geoff
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