Message-ID: <4C862773.2070900@gmx.net>
Date: Tue, 07 Sep 2010 13:52:19 +0200
From: Andreas <maps.on@gmx.net>
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To: pgsql-sql@postgresql.org
Subject: is there a distinct function for comma lists ?
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  Hi,
is there a distinct function for comma separated lists ?

I sometimes need to update tables where I got a set of IDs, like:

update mytable
    set someattribute = 42
where mytable.id in
(  1, 2, 3, 5, 7, 11, 3, 6, 13, 13, 3, 11 ... )

So there are double entries in the list but in this case its just 
overhead but no problem.

But for calculated values this would not allways be desirable.

update mytable
    set someattribute = someattribute + 1
where mytable.id in
(  1, 2, 3, 5, 7, 11, 3, 6, 13, 13, 3, 11 ... )

How could I get a distinct list? Those lists can have 2000-3000 IDs 
sometimes.

One solution was as follows but perhaps there is something more elegant?

update mytable
    set someattribute = someattribute + 1
where mytable.id in
  ( select distinct id from mytable where id in (  1, 2, 3, 5, 7, 11, 3, 
6, 13, 13, 3, 11 ... ) )


And as bonus ... is there a way to find IDs that are in the list but not 
in the table without creating a temporary table and use a join?