Aggregate Function to return most common value for a column

From: "Michael Harris" <michael(dot)harris(at)ericsson(dot)com>
To: <pgsql-general(at)postgresql(dot)org>
Subject: Aggregate Function to return most common value for a column
Date: 2009-05-22 07:48:44
Message-ID: E5F4C5A18CAB7A4DA23080DE9CE815860834FC61@eaubrmw001.eapac.ericsson.se
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Hi Experts,

I want to use an aggregate function that will return the most commonly
occurring value in a column.

The column consists of VARCHAR(32) values.

Is it possible to construct such an aggregate using PL/PgSql ?

If I was trying to do something like this in Perl I would use a hash
table to store the values and the number of times each was seen as the
table was iterated, but PL/PgSql does not seem to have an appropriate
data type for that?

I don't want to use PL/Perl to avoid the overhead of starting a perl
interpreter for that.

Do I have to write the function in C maybe?

Thanks in advance,
Regards
Mike Harris

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