[mysql] 연령대별 집계(통계) 구하기

SELECT TIMESTAMPDIFF(YEAR, BIRTH_DATE, NOW()) DIV 10 * 10 BIRTH 
       , COUNT(*) CNT 
 FROM EMPLOYEES E 
      , SALARIES S  
WHERE S.EMP_NO=E.EMP_NO  
  AND TO_DATE='9999-01-01' 
GROUP BY TIMESTAMPDIFF(YEAR, BIRTH_DATE, NOW()) DIV 10 
;