From: | postgres-novice(at)coreland(dot)ath(dot)cx |
---|---|
To: | pgsql-novice(at)postgresql(dot)org |
Subject: | Remove duplicate rows and order by number of occurences |
Date: | 2009-01-29 17:04:06 |
Message-ID: | 20090129170406.GB93056@logik.internal.network |
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Lists: | pgsql-novice |
Hello.
I'm trying to SELECT from the following table:
file_id
---------
1
1
2
3
5
6
9
9
9
10
10
The result I'm trying to achieve is essentially to order the
file_id column, in descending order, by the number of times
each row occurs with a given value. I would also like to remove
duplicate rows. In other words, the above table becomes
(approximately):
file_id
---------
9
10
1
6
5
3
2
The order of the last four values isn't significant (they occur
an equal number of times).
I thought that this might be the solution:
SELECT file_id FROM temp_tagged;
GROUP BY file_id
ORDER BY count (file_id) DESC;
But apparently, it isn't.
Any help would be appreciated.
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Next Message | Oliveiros Cristina | 2009-01-29 17:21:08 | Re: Remove duplicate rows and order by number of occurences |
Previous Message | Carol Walter | 2009-01-29 16:13:11 | Re: REALLY stupid question |