From: Martin Ramsch
Date: March 20 1999 6:43pm
Subject: Re: Help with query, plz
List-Archive: http://lists.mysql.com/mysql/693
Message-Id: <19990320194359.A28496@forwiss.uni-passau.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii

On Sa, 1999-03-20 11:25:51 -0700, Thimble Smith wrote:
> COUNT(DISTINCT(...)) doesn't work in MySQL (yet).  Try this:
> 
> SELECT COUNT(*) FROM table GROUP BY ip;

Not again!  I really wonder why people keep on giving this wrong
answer ...?

Thimble, this query only gives how many of each distinct value you
have, but not the number of distinct values.

The right answer is that it's not possible to do
  SELECT COUNT(DISTINCT field) ...
or equivalent with a single SQL query using MySQL up to 3.22.20a.

But, if you're not restricted to the SQL level only, as in most cases
where you use some host language to handle your queries, look at the
function mysql_num_rows() in MySQL's API.  If you can access this
functionality with your host language, then just
  SELECT DISTINCT field FROM table;
and then get the number of results.

Regards,
  Martin
-- 
Martin Ramsch <m.ramsch@stripped> <URL: http://home.pages.de/~ramsch/ >
PGP KeyID=0xE8EF4F75 FiPr=52 44 5E F3 B0 B1 38 26  E4 EC 80 58 7B 31 3A D7