【leetcode Database】177. Nth Highest Salary
题目:
Write a SQL query to get the nth highest salary from the Employee
table.
+----+--------+
| Id | Salary |
+----+--------+
| 1 | 100 |
| 2 | 200 |
| 3 | 300 |
+----+--------+
For example, given the above Employee table, the nth highest salary where n = 2 is 200
. If there is no nth highest salary, then the query should return null
.
解析:
把所有salary去重后排序,然后通过limit方法取出第n大的数。代码如下:
CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INT
BEGIN
DECLARE N1 INT;
SET N1 = N-1;
RETURN (
# Write your MySQL query statement below.
SELECT Salary FROM (SELECT DISTINCT Salary FROM Employee) e ORDER BY Salary DESC LIMIT N1,1
);
END
注意:limit后面一定不能写N-1,因为limit后面不能跟表达式。
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