SQL中的条件更新使用if或case

Question

我的问题是，是否有办法进行条件更新，例如

if existence = true 
    then update market set exitdate = now(), existence = false
    else then update market set exitdate = null, existence = true

对于我想要的更多内容，我找不到与我的代码类似的内容。

Answer 1

我用下一个代码解决了......

UPDATE market 
SET exitdate = CASE WHEN existence = true AND boxnumm = xxxx then now() else null END,
    existence = CASE WHEN exitdate <> null AND boxnumm = xxxx then false else true END
    WHERE boxnumm = xxxx
;