Bei folgendem SELECT gibt die nette Meldung MySQL Database Error: Mixing of GROUP columns (MIN(),MAX(),COUNT(),…) with no GROUP columns is illegal if there is no GROUP BY clause SELECT SUM(s\_articles\_groups\_value.instock - s\_order\_basket.quantity) AS diffStock, s\_order\_basket.ordernumber FROM s\_articles,s\_articles\_groups\_value,s\_order\_basket WHERE s\_articles.MODE = 0 AND s\_articles.active = 1 AND s\_articles.laststock = 1 AND s\_articles.id = s\_articles\_groups\_value.articleID AND s\_articles\_groups\_value.ordernumber = s\_order\_basket.ordernumber AND s\_order\_basket.modus = 0 AND s\_order\_basket.sessionID = 'xxyyzz' Ich habs erstmal umgangen, in dem ich an das Ende des SELECTS die Klausel GROUP BY s_order_basket.ordernumber gehangen hab.