从多行增加相同的列值

问题描述：

I'm using the blow query to update a column in multiple rows:

UPDATE table SET col = 
(case 
    when id = 1 then 10
    when id = 2 then 20
    when id = 3 then 30
end)

And I know if I want to increase the col value I should do this:

UPDATE table SET col = col+10

But it doesn't work for updating multiple rows.
I also tried:

when id = 1 then (@col := @col + 10)

But this doesn't work too.
Anyone knows how can I concatenate these two with each other and increase one column's value in multiple rows in mysql ?

我正在使用点击查询来更新多行中的列： p> UPDATE表SET col = （case = n当id = 1然后10 当id = 2然后20 当id = 3然后30 end） code> pre >

我知道如果我想增加 col code>值，我应该这样做： p>

  UPDATE table SET col =  col + 10 
  code>  pre> 
 
 但它不能用于更新多个 strong>行。
 
我也尝试过： p>  
 
  当id = 1然后（@col：= @col + 10）
  code>  pre> 
 
 
但这也不起作用。  
 
任何人都知道如何将这两者相互连接，并且在mysql的多行中增加一列的值？ strong>  p> 
  div>

答

If I understood you right:

UPDATE table SET col = col +
(case 
    when id = 1 then 10
    when id = 2 then 20
    when id = 3 then 30
end)

答

Looking for this?

UPDATE table SET col = if(@col is null, @col := col+10, @col)

or this?

UPDATE table SET col = if(id = 1, col+10, if(id = 2, col + 20, col + 30))

从多行增加相同的列值

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