摘要: 第二高的薪水,查第二高的人的信息 1、使用ifnull(exp1, exp2)函数,limit offset子句 select ifnull( (select distinct salary from Employee order by salary desc limit 1 offset 1), 阅读全文
posted @ 2023-03-29 16:48 Carl_ZhangJH 阅读(19) 评论(0) 推荐(0)
摘要: 组合两个表 使用左连接 left join select p.firstName, p.lastName, a.city, a.state from Person as p left join Address as a on a.PersonId = p.PersonId 阅读全文
posted @ 2023-03-29 14:40 Carl_ZhangJH 阅读(8) 评论(0) 推荐(0)