How To Find Duplicate Values in MySQL
http://www.mysqltutorial.org/mysql-find-duplicate-values/ SELECT mem_name, COUNT(mem_name) FROM mem_password GROUP BY mem_name HAVING COUNT(mem_name) > 1 ***************************************************************************************************************** compare row number and value form two different table SELECT COUNT(member_info.mem_name) as milon, mess_info.mess_mem_num,mess_info.mess_name FROM member_info INNER join mess_info on mess_info.mess_name=member_info.mess_name GROUP BY member_info.mess_name