Hi I found the solution myself,
but perhaps someone is interested as well.
SELECT count(*)
FROM table
WHERE attr IN (
SELECT attr
FROM table
WHERE condition
GROUP BY attr
HAVING count(*)>1
);
--
Regards,
Mit freundlichem Gruß,
Holger Klawitter
--
Holger Klawitter +49 (0)251 484 0637
holger(at)klawitter(dot)de http://www.klawitter.de/