Inert, Replica 81mm Illumination Mortar Round - Cut Away

1055 Expression #1 of ORDER BY clause is not in GROUP BY clause and contains nonaggregated column 'armytrai_militau4_znc1.o.date_purchased' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by
in:
[select p.products_id, p.products_image from znc_orders_products opa, znc_orders_products opb, znc_orders o, znc_products p where opa.products_id = '22639' and opa.orders_id = opb.orders_id and opb.products_id != '22639' and opb.products_id = p.products_id and opb.orders_id = o.orders_id and p.products_status = 1 group by p.products_id order by o.date_purchased desc limit 6]