order by xx and xx这是什么语法

Question

order by xx and xx
这是什么语法，执行还不会报错。

select sum(total) 
from orders 
order by deal and unit_price > 1000;

Answer 1

活见久，坐等大佬解释。
见过SELECT * FROM table_name ORDER BY column1 ASC|DESC , column2 ASC|DESC 这样的sql，还没见过后面拼接and