根据条件更新查询

Question

我想做以下几点.根据另一个字段的值更新字段

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,但它是我描述问题的最佳方式.

Answer 1

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

根据你的评论试试这个:

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