FROM as a Slicer
Besides the WHERE clause, MDX provides a second method of slicing the cube. This is the FROM clause. And the FROM clause is not limited only to a cube. A SELECT (a.k.a. sub-select, sub-query) can be used instead:
SELECT [Measures].Members ON 0, [Geography].[Geo].Members ON 1 FROM (SELECT [Time].[Calendar].[Year]. ON 0 FROM [Sales])
This is equivalent to the previous query slicing the results for the [Year].. Sub-selects/queries allow you to filter the dimensions (and the facts) of the cube to be queried.
To get more details about sub-queries, several illustrated working examples are available from our MDX documentation pages here.
Next chapter: Hierarchy Navigation.
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