GROUP BY 函数和HAVING()函数.

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Group By函数用于分组,以某一列名来进行分组,将相同项合并

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_nameWHERE column_name operator valueGROUP BY column_nameHAVING aggregate_function(column_name) operator value

例如:
SELECT Customer,SUM(OrderPrice) FROM OrdersWHERE Customer='Bush' OR Customer='Adams'GROUP BY CustomerHAVING SUM(OrderPrice)>1500

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