Aggregate Function to return most common value for a column

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