SQL SERVER 2012 第三章 T-SQL 基本语句 having子句

SELECT ManagerID AS Manager,COUNT(*) AS Reports FROM Human.Resources.Employee2 WHERE EmployeeID !=5 GROUP BY ManagerID HAVING COUNT(*)>3;

having 是聚合以后算的，很棒。where 是聚合以前算的。

用FOR XML子句可以输出XML格式。

ALL DISTINCT的用法。