更新與計算

Question

我試圖做從SELECT的UPDATE繼this SO thread

它不工作中給出的格式。我想知道是否因爲我在執行計算時需要不同的UPDATE ... SELECT結構。

我試過的下列各種版本：

 UPDATE tbl_usertime uat 
      SET uat.delay_qual = (TIMESTAMPDIFF(MINUTE, uat.view_date, '2011-10-11 15:22:25') > adt.delay), 
      freq_qual = (adt.frequency > uat.imps_today) 
     FROM tbl_timing adt 
     JOIN tbl_usertime uat 
      ON uat.ad_id = adt.ad_id; 

...但它在SQL語法錯誤...近 '返回從tbl_timing ADT JOIN tbl_usertime UAT'

任何想法？ 謝謝！

Answer 1

MySQL的語法是有點不同，試試這個：

update tbl_usertime uat join tbl_timing adt on uat.ad_id=adt.ad_id set 
    uat.delay_qual = (TIMESTAMPDIFF(MINUTE, uat.view_date, '2011-10-11 15:22:25') > adt.delay), 
     freq_qual = (adt.frequency > uat.imps_today) 

Answer 2

我不知道它會工作，但閱讀MySQL的文檔給我的感覺，可能是有效的：

UPDATE tbl_usertime join tbl_timing 
SET tbl_usertime.delay_qual = (TIMESTAMPDIFF(MINUTE, tbl_usertime.view_date, '2011-10-11 15:22:25') > tbl_timing.delay), 
    freq_qual = (tbl_timing.frequency > tbl_usertime.imps_today) 
where 
tbl_usertime.ad_id = tbl_timing.ad_id;