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To: pgsql-sql@postgresql.org
Subject: Re: LIMIT within UNION?
References: <Pine.LNX.4.21.0209121454540.32000-100000@perrin.socsci.unc.edu>
From: Roland Roberts <roland@astrofoto.org>
Date: 12 Sep 2002 15:35:14 -0400
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>>>>> "Andrew" == Andrew Perrin <clists@perrin.socsci.unc.edu> writes:

    Andrew> What I've done is to write a script that counts the number
    Andrew> of eligible exposure candidates:

    Andrew> SELECT count(*) FROM participants WHERE <eligibility>
    Andrew>  AND typenr=1

    Andrew> Then subtract that number (currently 28) from 200 to get
    Andrew> 172 control participants. Then the problem starts.

    [...]

    Andrew> returns ERROR:  parser: parse error at or near "ORDER"

Can you do this via a subselect:

SELECT * FROM 
    ( SELECT ... FROM participants
      WHERE typenr=1 AND <eligibility>
      UNION
      SELECT ... FROM participants
      WHERE typenr=2 LIMIT 172 )
ORDER BY zip;

roland
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