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Re: using 'count' to show number of dupes

From: "Loftis, Charles E" <charles(dot)loftis(at)eds(dot)com>
To: pgsql-novice(at)postgresql(dot)org
Subject: Re: using 'count' to show number of dupes
Date: 2004-07-12 17:50:39
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-novice
Write a queries like this...

   SELECT col1, count(col1) as count_col1
   FROM <table>
   GROUP BY col1

-----Original Message-----
From: pgsql-novice-owner(at)postgresql(dot)org
[mailto:pgsql-novice-owner(at)postgresql(dot)org] On Behalf Of Andy Harrison
Sent: Monday, July 12, 2004 1:29 PM
To: pgsql-novice(at)postgresql(dot)org
Subject: [NOVICE] using 'count' to show number of dupes

I'm writing some perl to sendmail maillog reporting.  Since the logs are too
big to some of the things I want to do, I'm just stuffing it to a pgsql db.
I'd like to offload as much of the work onto the db as much as possible.

How can I use count to show rows with the same value in the column?

col1   col2   col3
foo1   bar1   baz1
foo2   bar1   baz2
foo3   bar2   baz3
foo4   bar3   baz4
foo5   bar1   baz5
foo6   bar2   baz6

So, what would get pg to show me that col2 has 3 'bar1' values, 2 'bar2'
values and 1 'bar1' value.

Andy Harrison

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Subject: Re: using 'count' to show number of dupes
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Subject: Re: Weird join...

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