SQL SERVER 2008 GROUP BY GROUPING SETS

【SQL SERVER 2008 GROUP BY GROUPING SETS】

使用 GROUPING SETS 的 GROUP BY 子句可以生成一个等效于由多个简单 GROUP BY 子句的 UNION ALL 生成的结果集。GROUPING SETS 可以生成等效于由简单 GROUP BY、ROLLUP 或 CUBE 操作生成的结果。GROUPING SETS、ROLLUP 或 CUBE 的不同组合可以生成等效的结果集。

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SELECT * FROM AdventureWorksDW.dbo.FactFinance

--常用的分组方法
SELECT TimeKey,SUM(Amount) FROM FactFinance
GROUP BY TimeKey

SELECT TimeKey,OrganizationKey,SUM(Amount) FROM FactFinance
GROUP BY TimeKey,OrganizationKey

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--合并显示(UNION ALL 的 GROUPING SETS 等效项)
SELECT TimeKey,NULL,SUM(Amount) FROM FactFinance
GROUP BY GROUPING SETS(TimeKey)
UNION ALL
SELECT NULL,OrganizationKey,SUM(Amount) FROM FactFinance
GROUP BY GROUPING SETS(OrganizationKey)

--分别按TimeKey分组和OrganizationKey分组，一起显示(同上结果)
SELECT TimeKey,OrganizationKey,SUM(Amount) FROM FactFinance
GROUP BY GROUPING SETS(OrganizationKey,TimeKey)

SELECT TimeKey,OrganizationKey,DepartmentGroupKey,SUM(Amount) FROM FactFinance
GROUP BY GROUPING SETS(DepartmentGroupKey,OrganizationKey,TimeKey)

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--按多层级分组
SELECT TimeKey,OrganizationKey,SUM(Amount) FROM FactFinance
GROUP BY GROUPING SETS
(
(TimeKey),
(OrganizationKey,TimeKey)
)

--等价于ROLLUP(但是有个全部总计)
SELECT TimeKey,OrganizationKey,SUM(Amount) FROM FactFinance
GROUP BY TimeKey,OrganizationKey WITH ROLLUP

--更多的分层小计
SELECT TimeKey,OrganizationKey,DepartmentGroupKey,SUM(Amount) FROM FactFinance
GROUP BY GROUPING SETS
(
(TimeKey),
(TimeKey,OrganizationKey),
(TimeKey,OrganizationKey,DepartmentGroupKey)
)