Re: Select Maximum Question

From: Stuart Rison <stuart(at)ludwig(dot)ucl(dot)ac(dot)uk>
To: fmorton(at)base2inc(dot)com, pgsql-general(at)postgresql(dot)org
Subject: Re: Select Maximum Question
Date: 1999-08-13 08:40:02
Message-ID: v04020a00b3d9891cf856@[128.40.242.190]
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>I want to do a select which only returns the highest revision
>level for each filename, so the select will return two rows,
>the first filename with revision = "3" and the second filename
>with revision set to "1".

Try

SELECT filename,max(revision) FROM <table>
GROUP BY filename;

You can add a WHERE clause before the GROUP BY to only look at certain
filenames (e.g. WHERE filename~'foo') or if you're looking for files with a
specific latest revision number (e.g. WHERE revision=3) and an ORDER BY
after the GROUP BY (e.g. ORDER BY filename).

HTH,

S.

+--------------------------+--------------------------------------+
| Stuart C. G. Rison | Ludwig Institute for Cancer Research |
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| Tel. +44 (0)207 878 4041 | UNITED KINGDOM |
| Fax. +44 (0)207 878 4040 | stuart(at)ludwig(dot)ucl(dot)ac(dot)uk |
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