姓名,性别,该性别所有员工的总数”,如果我们使用传统的写法,那一定会涉及到子查询
SELECT s.Sname,s.Ssex, (SELECT COUNT(*) FROM dbo.Student a WHERE a.Ssex=s.Ssex) AS GenderTotal FROM dbo.Student s
如果我们使用了窗口函数,代码瞬间就变得简洁,不再需要子查询或Join
SELECT s.Sname,s.Ssex, COUNT(*) OVER (PARTITION BY Ssex) GenderTotal FROM dbo.Student s
查询结果