Date: Sun, 27 Nov 2005 09:50:41 +0100
From: Andreas Kretschmer <akretschmer@spamfence.net>
To: pgsql-sql@postgresql.org
Subject: Re: MAX, MIN and arrays
Message-ID: <20051127085041.GA2081@kaufbach.delug.de>
References: <Pine.LNX.4.62.0511261208320.8351@cetus5.cs.utk.edu>
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Colton A Smith <smith@cs.utk.edu> schrieb:

> Hi:
> 
>    Let's say I have a table with a column of one-dimensional arrays.  What 
> exactly is returned when the database is queried for a maximum from that 
> particular column?  The array was the greatest average value?  Let's say

What du you expect?

test=# select * from foo;
 id |   bar
----+---------
  1 | {1,2,3}
  2 | {2,2,2}
  3 | {3,2,1}
(3 rows)

Which row is the max()?


test=# select max(bar) from foo;
   max
---------
 {3,2,1}
(1 row)


It compares the first value in every array. If you wish to compare the
array depending on a other column, you can use somethink like

test=# select id, bar from foo order by bar ;
 id |   bar
----+---------
  1 | {1,2,3}
  2 | {2,2,2}
  3 | {3,2,1}
(3 rows)

test=# select id, bar from foo order by bar[3] ;
 id |   bar
----+---------
  3 | {3,2,1}
  2 | {2,2,2}
  1 | {1,2,3}
(3 rows)


> I have a table with a column of two-dimensional arrays.  What then?

The same.


HTH, Andreas
-- 
Really, I'm not out to destroy Microsoft. That will just be a completely
unintentional side effect. (Linus Torvalds)
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