SELECT birthday age, COUNT(*)VALUE FROM t_member WHERE TIMESTAMPDIFF(YEAR,birthday,NOW()) BETWEEN 0 AND 18
SELECT birthday age, COUNT(*)VALUE FROM t_member WHERE TIMESTAMPDIFF(YEAR,birthday,NOW()) BETWEEN 19 AND 30
SELECT birthday age, COUNT(*)VALUE FROM t_member WHERE TIMESTAMPDIFF(YEAR,birthday,NOW()) BETWEEN 31 AND 45
SELECT birthday age, COUNT(*)VALUE FROM t_member WHERE TIMESTAMPDIFF(YEAR,birthday,NOW())>45