mysql 批量 update 问题 - V2EX
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FenixVu
V2EX    MySQL

mysql 批量 update 问题

  •  
  •   FenixVu 2020-07-09 17:17:22 +08:00 2590 次点击
    这是一个创建于 1995 天前的主题,其中的信息可能已经有所发展或是发生改变。

    |cno |cname |tno | |1001|zhangsan|101| |1002|zhangsan|102| |1003|zhangsan|103|

    UPDATE course SET cno = CASE tno WHEN 1001 THEN '1.57' WHEN 1002 THEN '1.3' WHEN 1003 THEN '1.2' END WHERE tno IN (1,2,3) 

    返回

    1 queries executed, 1 success, 0 errors, 0 warnings 查询:UPDATE course SET cno = CASE tno WHEN 1001 THEN '1.57' WHEN 1002 THEN '1.3' WHEN 1003 THEN '1.2' END WHERE tno IN (1,2,3) 共 0 行受到影响 执行耗时 : 0 sec 传送时间 : 0 sec 总耗时 : 0.001 sec 

    为啥???

    8 条回复    2020-07-09 20:11:43 +08:00
    zshneedmoney
        1
    zshneedmoney  
       2020-07-09 17:27:10 +08:00
    啥意思?这没有符合条件的数据可不就是 0 行收到影响
    FenixVu
        2
    FenixVu  
    OP
       2020-07-09 17:33:34 +08:00
    @zshneedmoney

    当条件 'tno' 是 1001 的时候 把 cno set 为 '1.57'
    难道是我理解错了么
    qiayue
        3
    qiayue  
    PRO
       2020-07-09 17:43:33 +08:00
    WHERE tno IN (1,2,3)
    要改成
    WHERE tno IN (1001,1002,1003)
    U7Q5tLAex2FI0o0g
        4
    U7Q5tLAex2FI0o0g  
       2020-07-09 17:46:37 +08:00
    你的 tno 不是 101,102,103 么,WHERE tno IN (1,2,3) 没有符合的数据
    DonaldY
        5
    DonaldY  
       2020-07-09 17:50:16 +08:00
    when 后面是表达 bool 吧。
    FenixVu
        6
    FenixVu  
    OP
       2020-07-09 19:10:07 +08:00
    @qiayue @littleylv 我试了下 都不太行...
    qiayue
        7
    qiayue  
    PRO
       2020-07-09 20:11:39 +08:00
    语法错了

    UPDATE course
    SET cno = CASE
    WHEN tno=1001 THEN '1.57'
    WHEN tno=1002 THEN '1.3'
    WHEN tno=1003 THEN '1.2'
    ELSE cno
    END
    WHERE tno IN (1001,1002,1003)
    JasonLaw
        8
    JasonLaw  
       2020-07-09 20:11:43 +08:00 via iPhone
    能够清楚地表达一下你的“为啥”是什么吗?反正我是不明白你的问题是什么
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