Error SQL:

QUERY:
SELECT DISTINCT productgroups.id, productgroups.text_name FROM `alfa_ru_productgroups` AS productgroups LEFT JOIN `alfa_ru_catalog` AS catalog ON productgroups.id = catalog.pselect_productgroups WHERE catalog.pselect_catalog_main = 50691 ORDER BY productgroups.ord ASC
MYSQL Error:
Expression #1 of ORDER BY clause is not in SELECT list, references column 'alfam3_alfa_m.productgroups.ord' which is not in SELECT list; this is incompatible with DISTINCT