MDX queries are complex compared to the SQL or TSQL queries. It is perceived as complex because the underlying data source is not two dimensional. But simple MDX expressions are not very complex, 😀 as that is why they are simple.

Members and the Children properties of the MDX provide different set of outputs for the hierarchies.

SELECT [Measures].[Internet Sales Amount] ON columns,
[Product].[Category].Children on rows
from [Adventure Works]
where [Date].[Calendar Year].&[2003]

As you see below, when you specify the Children the it excludes the ‘All’ member of the hierarchy.

select [Measures].[Internet Sales Amount] on columns,
[Product].[Category].Members on rows
from [Adventure Works]
where [Date].[Calendar Year].&[2003]

‘Members’ brings you the results with the ‘All’.