mysql - 是否可以在一个查询中更新同一列中的 2 个字段（mysql）

Question

我有一个名为“系统”的表有 2 列“变量”和“值”，其中包含以下数据：

• 变量 = '用户名' => 值 = 'myuser'
• 变量 = '密码' => 值 = 'mypass'

我想在 1 个查询中更新这 2 个字段。

2个查询是：

UPDATE System SET Value = 'myuser' WHERE Variable = 'Username'
UPDATE System SET Value = 'mypass' WHERE Variable = 'Password'

Answer 1

UPDATE System
SET Value = (CASE
    WHEN Variable = 'Username' THEN 'myuser'
    WHEN Variable = 'Password' THEN 'mypass'
  END)
 WHERE Variable = 'Username' or Variable = 'Password'

Answer 2

是的，使用他的案例陈述：

UPDATE System
    SET Value = (case when Variable = 'UserName' then 'myuser'
                      when Variable = 'Password' then 'mypass'
                      else Value
                 end)
    WHERE Variable in ('Username', 'Password');

Answer 3

UPDATE System SET `Value` = IF(`Variable`='Username', 'myuser', 'mypassw') 
WHERE `Value` IN ('Username', 'Password');

Answer 4

UPDATE System 
SET Value = case when Variable = 'Username' then 'myuser' 
                 when Variable = 'Password' then 'mypass' 
            end
WHERE Variable in ('Username', 'Password')

Answer 5

UPDATE System SET
 Value = (case Variable when 'Username' then 'myuser' when 'Password' then 'mypass' end)
WHERE Variable  = 'Username' or Variable = 'Password'