摘要： 参考：https://www.cnblogs.com/sword082419/p/9097749.html https://www.w3school.com.cn/sql/sql_join.asp 注意：MySQL中JOIN与INNER JOIN是等价的， 即默认是 内连接 阅读全文

摘要： 力扣：第二高薪水 https://leetcode-cn.com/problems/second-highest-salary/ SELECT (SELECT Salary FROM Employee ORDER BY Salary DESC LIMIT 1 OFFSET 1) AS SecondH 阅读全文