Problem preparing query (SELECT pac.id_atributo_producto, GROUP_CONCAT(agl.`nombre`, ' - ',al.`nombre` ORDER BY agl.`id_atributo_grupo` SEPARATOR ', ') as attribute_designation, GROUP_CONCAT(agl.`id_atributo_grupo`, '-',al.`id_atributo` ORDER BY agl.`id_atributo_grupo` SEPARATOR ',') as attribute_designation_ids FROM `productos_atributos_combinaciones` pac LEFT JOIN `atributos` a ON a.`id_atributo` = pac.`id_atributo` LEFT JOIN `atributos_grupos` ag ON ag.`id_atributo_grupo` = a.`id_atributo_grupo` LEFT JOIN `atributos_idioma` al ON (a.`id_atributo` = al.`id_atributo` AND al.`id_idioma` = 1) LEFT JOIN `atributos_grupos_idioma` agl ON (ag.`id_atributo_grupo` = agl.`id_atributo_grupo` AND agl.`id_idioma` = 1) WHERE pac.id_atributo_producto IN () GROUP BY pac.id_atributo_producto) 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 pac.id_atributo_producto' at line 8