逻辑函数对对象和表达式执行逻辑操作或比较,并返回一个布尔值。 逻辑函数在多维表达式(MDX)中是确定成员位置的关键。
最常用的逻辑函数是 IsEmpty 函数。 有关如何使用 IsEmpty 函数的更多信息,请参见 “处理空值”。
以下查询展示了如何使用 IsLeaf 和 IsAncestor 函数:
WITH
//Returns true if the CurrentMember on Calendar is a leaf member, ie it has no children
MEMBER MEASURES.[IsLeafDemo] AS IsLeaf([Date].[Calendar].CurrentMember)
//Returns true if the CurrentMember on Calendar is an Ancestor of July 1st 2001
MEMBER MEASURES.[IsAncestorDemo] AS IsAncestor([Date].[Calendar].CurrentMember, [Date].[Calendar].[Date].&[1])
SELECT{MEASURES.[IsLeafDemo],MEASURES.[IsAncestorDemo] } ON 0,
[Date].[Calendar].MEMBERS ON 1
FROM [Adventure Works]