SQL 50 › 索引 › A7 Advanced String Functions / Regex / Clause 高级字符串函数与正则
LC 176第二高的薪水Second Highest Salary 中等
Employee 表存员工工资;查询第二高的不同工资值,若不存在则返回 NULL。
思路 取小于 MAX 的最大值;亦可 ORDER BY DESC LIMIT 1 OFFSET 1 + IFNULL。
SELECT MAX(salary) AS SecondHighestSalary FROM Employee WHERE salary < (SELECT MAX(salary) FROM Employee);