[LeetCode] Nth Highest Salary 第N高薪水

题目
编写一个 SQL 查询,获取 Employee表中第 n 高的薪水(Salary)。

+----+--------+
| Id | Salary |
+----+--------+
| 1  | 100    |
| 2  | 200    |
| 3  | 300    |
+----+--------+

例如上述 Employee 表,n = 2 时,应返回第二高的薪水 200。如果不存在第 n 高的薪水,那么查询应返回 null

+------------------------+
| getNthHighestSalary(2) |
+------------------------+
| 200                    |
+------------------------+

解法

CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INT
BEGIN
  SET N = N - 1;
  RETURN (
      SELECT DISTINCT Salary FROM Employee GROUP BY Salary
      ORDER BY Salary DESC LIMIT 1 OFFSET N
  );
END

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转载自www.cnblogs.com/qiuhuashan/p/11060540.html