从多行增加相同的列值

Question

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 ?

Answer 1

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)