如果条件按顺序，Mysql不能使用mysql

I want to write a select like this

我想写一个像这样的选择

if(`order` > 0)
    Order BY category_id, arder
if(`order` = 0)
    Order BY id

But in this select does not work

但在这个选择不起作用

SELECT *  from post 
ORDER BY if(`order` > 0,  ( category_id, `order`) ,  id)

1 个解决方案

"If" is an expression returns a value, I don't think you can use it to change the "order by" statement itself.

“如果”是一个表达式返回一个值,我认为你不能用它来改变“order by”语句本身。

You can try something like this:

你可以尝试这样的事情:

select *, case when order>0 then category_id else 0 end cat_id, id
from post
order by cat_id, order, id