1. 下圖為使用者聽歌記錄表recordTime：
   
2. 下圖為歌曲表music：
   
3. 現在需要計算每首歌被聽數，並將其儲存到歌曲表中，mysql語句為：

UPDATE music D
  LEFT JOIN (SELECT 
        B.musicId,
                count(*) AS s_sum
           FROM recordTime B
          GROUP BY B.musicId) C
    ON (C.musicId = D.musicId)
   SET D.listenTimes = c.s_sum
 WHERE D.musicId = 
       (
         SELECT
 
 
        E.id FROM 
        (
                  SELECT 
                DISTINCT a.musicId AS id
                    FROM recordTime A
                ) E 
          WHERE E.id = D.musicId
       )