Re: [GENERAL] Any ideas why this doesn't work or how to rewrite it?

From: "Brett W(dot) McCoy" <bmccoy(at)lan2wan(dot)com>
To: Herouth Maoz <herouth(at)oumail(dot)openu(dot)ac(dot)il>
Cc: Aaron Holtz <aholtz(at)bright(dot)net>, pgsql-general(at)postgreSQL(dot)org
Subject: Re: [GENERAL] Any ideas why this doesn't work or how to rewrite it?
Date: 1999-04-29 18:04:45
Message-ID: Pine.BSI.3.91.990429140136.6326F-100000@access1.lan2wan.com
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On Thu, 29 Apr 1999, Herouth Maoz wrote:

> At 18:50 +0300 on 28/04/1999, Aaron Holtz wrote:
>
>
> > db=> select count(distinct customer_username) from customerdata;
> > ERROR: parser: parse error at or near "distinct"
> >
> > How do you get a count of distinct data output via postgres? I can always
> > just count the number of tuples returned but this seemed to be a valid
> > query.
>
> Valid it is, but not yet supported in PostgreSQL.
>
> An (ugly) workaround would be something along the lines of:
>
> SELECT count(customer_username)
> FROM customerdata c1
> WHERE int( oid ) = (
> SELECT min( int( c2.oid ) )
> FROM customerdata c2
> WHERE c1.customer_username = c2.customer_username
> );

I think, Aaron, you could get a count of distinct customer names like this:

SELECT DISTINCT customer_username, COUNT(*) FROM customerdata
GROUP BY customer_username;

This will give you 2 columns, one with the distinct customer_usernames
and the second with the count of each. The GROUP BY caluse is important
here. This looks like what you wanted in your original query.

Brett W. McCoy
http://www.lan2wan.com/~bmccoy
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