Error: SELECT elementClass, reqFunct FROM core_elements WHERE reqFunct is not null AND reqFunct <> '' AND active = 1 GROUP BY elementClass

Expression #2 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'timizoli_site.core_elements.reqFunct' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by