Similar to calculated members, a named set is an MDX expression defining the content of a set that can then be used wherever a set is expected. Named sets can be defined within the scope of a SELECT expression. Note that they're evaluated in the context of the slicer, if available:
WITH SET [European Countries] AS [Geography].[Geo].[Europe].Children SELECT [Measures].[Amount] ON COLUMNS, [European Countries] ON ROWS FROM [Sales]
The example above is selecting the amount of sales for each European country.
The named sets also have scope. When the set is defined in the query by using the SET clause, as shown above, the scope of the set is only limited to the lifetime of the query. When the query executes again, the set is re-calculated. When the SET is defined in the cube itself, it can be of either session or of global scope.
We've now reached the end of our gentle MDX introduction. The following pages describe in more detail each MDX function and several features of MDX.
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