Mysql Group by not working! here have a solution..

#1055 - Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'billing_system.orders.order_id' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by

Simply Type 

SET GLOBAL sql_mode=(SELECT REPLACE(@@sql_mode,'ONLY_FULL_GROUP_BY',''));

And run sql...

Thank You... :-)