《Microsoft SQL Server 2008 MDX Step by Step》学习笔记九：导航结构层次
SQL Server 2008中SQL应用系列及BI学习笔记系列--目录索引
导读:本文介绍MDX中的导航结构层次（Hierarchies）。成员（Member）之间的关系可以用家族来描述。本文以此为基础，介绍了：
■1、访问直系亲属关系（Immediate Relatives）
■2、访问延伸亲属关系（Extended Relatives）
■3、在一个级别（Level）内导航
本文所用数据库和所有源码，请到微软官网下载
成员（Member）之间的关系可以用家族来描述。（其中Siblings是兄弟、旁支的意思，照顾下E文不好的朋友，呵呵）
下面我们以此为类，演示如何访问直系亲属和非直系亲属。
1、访问直系亲属关系（Immediate Relatives）
直系亲属的访问函数如下：
为了更好理解直系亲属关系，准备一个原始例子
例8-1
SELECT
{([Measures].[Reseller Sales Amount])} ON COLUMNS,
{[Product].[Subcategory].[Subcategory].Members} ON ROWS
FROM [Step-by-Step]
;
我们增加Parent属性:
例8-2
WITH
MEMBER [Measures].[Percent of Parent] AS
([Measures].[Reseller Sales Amount])/
(
[Product].[Product Categories].CurrentMember.Parent,
[Measures].[Reseller Sales Amount]
)
,FORMAT="Percent"
SELECT
{
([Measures].[Reseller Sales Amount]),
([Measures].[Percent of Parent])
} ON COLUMNS,
{[Product].[Product Categories].Members} ON ROWS
FROM [Step-by-Step]
;
这个结果还有有一些刺眼，特别是第一条记录这样的。因为除数为0。
我们改进一下：
例8-3
WITH
MEMBER [Measures].[Percent of Parent] AS
IIF(
[Product].[Product Categories].CurrentMember.Parent Is Null,
Null,
([Measures].[Reseller Sales Amount])/
(
[Product].[Product Categories].CurrentMember.Parent,
[Measures].[Reseller Sales Amount]
)
)
,FORMAT="Percent"
SELECT
{
([Measures].[Reseller Sales Amount]),
([Measures].[Percent of Parent])
} ON COLUMNS,
{
[Product].[Product Categories].Members
} ON ROWS
FROM [Step-by-Step]
;
顺便我们介绍一个有用的函数Rank（http://msdn.microsoft.com/zh-cn/library/ms144726.aspx），与SQL中的Rank类似。
例如如下查询：
例8-4
SELECT
{([Measures].[Reseller Sales Amount])} ON COLUMNS,
{[Product].[Product Categories].Members} ON ROWS
FROM [Step-by-Step]
;
我们进行排名：
例8-5
WITH
MEMBER [Measures].[Sibling Rank] AS
Rank(
[Product].[Product Categories].CurrentMember,
[Product].[Product Categories].CurrentMember.Siblings,
([Measures].[Reseller Sales Amount])
)
SELECT
{
([Measures].[Reseller Sales Amount]),
([Measures].[Sibling Rank])
} ON COLUMNS,
{[Product].[Product Categories].Members} ON ROWS
FROM [Step-by-Step]
;
排名有了，再改进一下排序：
例8-6
WITH
MEMBER [Measures].[Sibling Rank] AS
Rank(
[Product].[Product Categories].CurrentMember,
[Product].[Product Categories].CurrentMember.Siblings,
([Measures].[Reseller Sales Amount])
)
SELECT
{
([Measures].[Reseller Sales Amount]),
([Measures].[Sibling Rank])
} ON COLUMNS,
{
Order(
{[Product].[Product Categories].Members},
([Measures].[Sibling Rank]),
ASC
)
} ON ROWS
FROM [Step-by-Step]
;
2、访问延伸亲属关系（Extended Relatives）
其中相比直系关系，多了几个Flag:
我们以上面的例8-3为例，首先我们增加一个Ancestor
例8-7
WITH
MEMBER [Measures].[Percent of Parent] AS
IIF(
[Product].[Product Categories].CurrentMember.Parent Is Null,
Null,
([Measures].[Reseller Sales Amount])/
(
[Product].[Product Categories].CurrentMember.Parent,
[Measures].[Reseller Sales Amount]
)
)
,FORMAT="Percent"
MEMBER [Measures].[Percent of Category] AS
([Measures].[Reseller Sales Amount])/
(
Ancestor(
[Product].[Product Categories].CurrentMember,
[Product].[Product Categories].[Category]
),
[Measures].[Reseller Sales Amount]
)
,FORMAT="Percent"
SELECT
{
([Measures].[Reseller Sales Amount]),
([Measures].[Percent of Parent]),
([Measures].[Percent of Category])
} ON COLUMNS,
{[Product].[Product Categories].Members} ON ROWS
FROM [Step-by-Step]
;
仿上，我们进行改进：
例8-8
WITH
MEMBER [Measures].[Percent of Parent] AS
IIF(
[Product].[Product Categories].CurrentMember.Parent Is Null,
Null,
([Measures].[Reseller Sales Amount])/
(
[Product].[Product Categories].CurrentMember.Parent,
[Measures].[Reseller Sales Amount]
)
)
,FORMAT="Percent"
MEMBER [Measures].[Percent of Category] AS
IIF(
Ancestor(
[Product].[Product Categories].CurrentMember,
[Product].[Product Categories].[Category]
) Is Null,
Null,
([Measures].[Reseller Sales Amount])/
(
Ancestor(
[Product].[Product Categories].CurrentMember,
[Product].[Product Categories].[Category]
),
[Measures].[Reseller Sales Amount]
)
)
,FORMAT="Percent"
SELECT
{
([Measures].[Reseller Sales Amount]),
([Measures].[Percent of Parent]),
([Measures].[Percent of Category])
} ON COLUMNS,
{[Product].[Product Categories].Members} ON ROWS
FROM [Step-by-Step]
;
下面我们尝试穿越“血缘关系”计算Product的百分比贡献。
例8-9
SELECT
{([Measures].[Reseller Sales Amount])} ON COLUMNS,
{([Product].[Product Categories].[Product].[Mountain-200 Black, 42])} ON ROWS
FROM [Step-by-Step]
;
例8-10
SELECT
{([Measures].[Reseller Sales Amount])} ON COLUMNS,
{
Ascendants(
[Product].[Product Categories].[Product].[Mountain-200 Black, 42]
)
} ON ROWS
FROM [Step-by-Step]
;
例8-11
SELECT
{([Measures].[Reseller Sales Amount])} ON COLUMNS,
Hierarchize(
{
Ascendants(
[Product].[Product Categories].[Product].[Mountain-200 Black, 42]
)
}
) ON ROWS
FROM [Step-by-Step]
;
例8-12
WITH
MEMBER [Measures].[Percent Contribution Reseller Sales] AS
(
[Product].[Product Categories].[Product].[Mountain-200 Black, 42],
[Measures].[Reseller Sales Amount]
) /
([Measures].[Reseller Sales Amount])
,FORMAT="Percent"
SELECT
{
([Measures].[Reseller Sales Amount]),
([Measures].[Percent Contribution Reseller Sales])
} ON COLUMNS,
Hierarchize(
{
Ascendants(
[Product].[Product Categories].[Product].[Mountain-200 Black, 42]
)
}
) ON ROWS
FROM [Step-by-Step]
;
下面我们组装一个给定分类的后裔集合
例8-13
SELECT
{([Measures].[Reseller Sales Amount])} ON COLUMNS,
{[Product].[Product Categories].[Category].[Bikes]} ON ROWS
FROM [Step-by-Step]
;
例8-14
SELECT
{([Measures].[Reseller Sales Amount])} ON COLUMNS,
Descendants(
{[Product].[Product Categories].[Category].[Bikes]},
[Product].[Product Categories].[Subcategory]
) ON ROWS
FROM [Step-by-Step]
;
例8-15
SELECT
{([Measures].[Reseller Sales Amount])} ON COLUMNS,
Descendants(
{[Product].[Product Categories].[Category].[Bikes]},
[Product].[Product Categories].[Subcategory],
AFTER
) ON ROWS
FROM [Step-by-Step]
;
After标志符提供了SubCategory以下的后裔集合
例8-16
SELECT
{([Measures].[Reseller Sales Amount])} ON COLUMNS,
Descendants(
{[Product].[Product Categories].[Category].[Bikes]},
[Product].[Product Categories].[Subcategory],
SELF_AND_AFTER
) ON ROWS
FROM [Step-by-Step]
;
SELF_AND_AFTER标志符提供了SubCategory及以下的后裔集合
例8-17
SELECT
{([Measures].[Reseller Sales Amount])} ON COLUMNS,
Descendants(
{[Product].[Product Categories].[Category].[Bikes]},
[Product].[Product Categories].[Subcategory],
BEFORE_AND_AFTER
) ON ROWS
FROM [Step-by-Step]
;
BEFORE_AND_AFTER标志符提供了包含SubCategory的上级分类的所有后裔集合
大家有兴趣可以了解一下几个相关的成员函数：
IsAncestor（http://msdn.microsoft.com/zh-cn/library/ms144842.aspx）
IsSibling（http://msdn.microsoft.com/zh-cn/library/ms144749.aspx）
IsLeaf（http://msdn.microsoft.com/zh-cn/library/ms144932.aspx）
例8-18
WITH
MEMBER [Measures].[Number of Children] AS
IIF(
IsLeaf([Product].[Product Categories].CurrentMember),
"N/A",
COUNT(
[Product].[Product Categories].CurrentMember.Children
)
)
SELECT
{[Measures].[Number of Children]} ON COLUMNS,
{[Product].[Product Categories].Members} ON ROWS
FROM [Step-by-Step]
3、在一个级别（Level）内导航
在一个级别内导航会用到几个函数：
比如计算月之间的百分比差距
例8-19
SELECT
{([Measures].[Reseller Sales Amount])} ON COLUMNS,
{[Date].[Calendar].[Month].Members} ON ROWS
FROM [Step-by-Step]
;
例8-20
WITH
MEMBER [Measures].[Prior Period Reseller Sales] AS
([Date].[Calendar].CurrentMember.PrevMember,[Measures].[Reseller Sales Amount])
,FORMAT="Currency"
SELECT
{
([Measures].[Reseller Sales Amount]),
([Measures].[Prior Period Reseller Sales])
} ON COLUMNS,
{[Date].[Calendar].[Month].Members} ON ROWS
FROM [Step-by-Step]
;
例8-21
WITH
MEMBER [Measures].[Prior Period Reseller Sales] AS
([Date].[Calendar].CurrentMember.PrevMember,[Measures].[Reseller Sales Amount])
,FORMAT="Currency"
MEMBER [Measures].[Change in Reseller Sales] AS
([Measures].[Reseller Sales Amount]) - ([Measures].[Prior Period Reseller Sales])
,FORMAT="Currency"
SELECT
{
([Measures].[Reseller Sales Amount]),
([Measures].[Prior Period Reseller Sales]),
([Measures].[Change in Reseller Sales])
} ON COLUMNS,
{[Date].[Calendar].[Month].Members} ON ROWS
FROM [Step-by-Step]
;
例8-22
WITH
MEMBER [Measures].[Prior Period Reseller Sales] AS
([Date].[Calendar].CurrentMember.PrevMember,[Measures].[Reseller Sales Amount])
,FORMAT="Currency"
MEMBER [Measures].[Change in Reseller Sales] AS
([Measures].[Reseller Sales Amount]) - ([Measures].[Prior Period Reseller Sales])
,FORMAT="Currency"
MEMBER [Measures].[Percent Change in Reseller Sales] AS
([Measures].[Change in Reseller Sales])/
([Measures].[Prior Period Reseller Sales])
,FORMAT="Percent"
SELECT
{
([Measures].[Reseller Sales Amount]),
([Measures].[Prior Period Reseller Sales]),
([Measures].[Change in Reseller Sales]),
([Measures].[Percent Change in Reseller Sales])
} ON COLUMNS,
{[Date].[Calendar].[Month].Members} ON ROWS
FROM [Step-by-Step]
;
如果觉得最后一列格式不够完美，读者可以自行修正一下。
小结：
本文介绍MDX中的导航结构层次（Hierarchies）。成员（Member）之间的关系可以用家族来描述。本文包含了比较多的函数。
参考资源：
1、MDX官方教程（http://msdn.microsoft.com/zh-cn/library/ms145506.aspx）