Invalid MySQL query: 1064: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'GROUP BY p.category' at line 5
 SELECT p.category
                     FROM foldingmachines_hub AS a
                     LEFT JOIN  prislista AS p ON ( = a.prislista_id )
                     WHERE a.foldingmachines_id = 
                     GROUP BY p.category