NonEmptySubset

Given an input set, NonEmptySubset returns a subset of that input set in which all tuples evaluate to nonempty. An optional value expression may be specified for the nonempty check.

This function can help optimize queries that are based on a large set for which the set of nonempty combinations is known to be small. NonEmptySubset reduces the size of the set in the presense of a metric; for example, you might request the nonempty subset of descendants for specific Units.

NonEmptySubset is used to reduce the size of a set before a subsequent analytical retrieval.

Syntax

NonEmptySubset (set [, value_expression [, dimension...]])

Notes

Value_expression, if used, should be a stored member or simple formula. If value_expression is a complex formula, the retrieval of the nonempty subset is not optimized.

Example

The following example gets the bottom 10 products in terms of Units (items per package), and then returns the CrossJoin of that set and the level 0 members (zip codes) of [Albany - NY].

WITH SET Bottom_10 
AS '
 BottomCount(
  Leaves(Products),
  10,
  Units
 )
'
SELECT 
 {Units} 
ON COLUMNS,
 NonEmptySubset(CrossJoin(Bottom_10, Leaves([Albany - NY])))
ON ROWS
FROM Asosamp.Sample

This query returns the following grid: