摘要：1 CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INT 2 BEGIN 3 SET N := N - 1; 4 RETURN ( 5 # Write your MySQL query statement below. 6 select (se 阅读全文

摘要：select (select distinct Salary from Employee order by Salary desc limit 1,1) as SecondHighestSalary 注意加distinct，如果不加这个关键字，无法通过测试。 阅读全文

摘要：leetcode数据库的题目，组合两个表，使用left join查询。 select p.FirstName,p.LastName,a.City,a.State from Person p left join Address a on p.PersonId = a.PersonId; 阅读全文