mysql - mysql查询中 "where(n) "到底是什么意思

Question

我看到一个在表中查找第 n 个最高薪水的查询:

SELECT *
FROM one one1
WHERE ( n ) = ( SELECT COUNT( one2.salary )
                FROM one one2
                WHERE one2.salary >= one1.salary
              )

可以解释一下这是如何工作的吗？这里的“WHERE(n)”是什么意思

Answer 1

它的名字是row constructor .

对于您的情况(标量子查询)括号是多余的，您可以仅使用:

SELECT *
FROM one one1
WHERE  n  = ( SELECT COUNT( one2.salary )
               FROM one one2
               WHERE one2.salary >= one1.salary
             )

但是当您需要比较多个值时，它很有用:

SELECT *
FROM t1
WHERE (col1,col2) = (SELECT col3, col4 FROM t2 WHERE id = 10);