在 SQL 中增加 HAVING 子句原因是,WHERE 關鍵字無法與合計函數一起使用。
語法:
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
例子1:查找訂單總金額少於 2000 的客戶
SELECT Customer,SUM(OrderPrice) FROM Orders GROUP BY Customer HAVING SUM(OrderPrice)<2000;
例子2:查找客戶 "Bush" 或 "Adams" 擁有超過 1500 的訂單總金額
SELECT Customer,SUM(OrderPrice) FROM Orders WHERE Customer='Bush' OR Customer='Adams' GROUP BY Customer HAVING SUM(OrderPrice)>1500;