sqi 2005 having语句 的用法和作用

HAVING 子句
在 SQL 中增加 HAVING 子句原因是,WHERE 关键字无法与合计函数一起使用.
SQL HAVING 语法
SELECT column_name, aggregate_function(column_name)
FROM table_name
WHERE column_name operator value
GROUP BY column_name
HAVING aggregate_function(column_name) operator value
SQL HAVING 实例
我们拥有下面这个 "Orders" 表：
O_Id OrderDate OrderPrice Customer
1 2008/12/29 1000 Bush
2 2008/11/23 1600 Carter
3 2008/10/05 700 Bush
4 2008/09/28 300 Bush
5 2008/08/06 2000 Adams
6 2008/07/21 100 Carter
现在,我们希望查找订单总金额少于 2000 的客户.
我们使用如下 SQL 语句：
SELECT Customer,SUM(OrderPrice) FROM Orders
GROUP BY Customer
HAVING SUM(OrderPrice)1500
结果集：
Customer SUM(OrderPrice)
Bush 2000
Adams 2000