根据条件更新查询 [英] Update Query based on condition

问题描述

我想做以下事情. 根据另一个字段的值更新一个字段，例如

I would like to do the following. Update a field based on the value of another field like

update table set if(fielda=1){fieldb=2 fieldc=3}else{fieldd=2 fielde=3}

我知道这不是有效的mysql，但这是我描述问题的最佳方法.

I know this is not valid mysql but its the best way for me to describe the problem.

推荐答案

update table set
b = case when a = 1 then 2 else b end,
c = case when a = 1 then 3 else c end,
d = case when a = 1 then d else 2 end,
e = case when a = 1 then e else 3 end

编辑

根据您的评论尝试以下操作:

edit

according to your comment try this:

update table set
datefield_a = case when field_a = 1 then now() else datefield_a end,
datefield_b = case when field_a <> 1 then now() else datefield_b end

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