摘要: 例子1:获取 Employee 表中第二高的薪水(Salary),没有第二高的则返回null select ifnull((select distinct Salary from Employee order by Salary desc limit 1, 1), null) as SecondHi 阅读全文
posted @ 2020-06-11 14:48 wanglai 阅读(176) 评论(0) 推荐(0) 编辑