Drills down the members in a specified set that are present in a second specified set, limiting the result set to a specified number of members. Alternatively, this function drills down on a set of tuples by using the first tuple hierarchy or the optionally specified hierarchy.
If a numeric expression is specified, the DrilldownMemberTop function sorts, in descending order, the children of each member in the first set according to the value of the numeric expression, as evaluated over the set of child members. If a numeric expression is not specified, the function sorts, in descending order, the children of each member in the first set according to the values of the cells represented by the set of child members, as determined by the query context. This behavior is similar to the TopCount and Head (MDX) functions which return a set of members in natural order, without any sorting.
After sorting, the DrilldownMemberTop function returns a set that contains the parent members and the number of child members, specified in Count, with the highest value and are contained in both sets.
If RECURSIVE is specified, the function sorts the first set as described previously, then recursively compares the members of the first set, as organized in a hierarchy, against the second set. The function retrieves the topmost number of children for each member in the first set that is also present in the second set.
The first set can contain tuples instead of members. Tuple drilldown is an extension of OLE DB, and returns a set of tuples instead of members.
The DrilldownMemberTop function is similar to the DrilldownMember function, but instead of including all children for each member in the first set that is also present in the second set, the DrilldownMemberTop function returns the topmost number of child members for each member.
Querying the XMLA property MdpropMdxDrillFunctions enables you to verify the level of support that the server provides for the drilling functions; see Supported XMLA Properties (XMLA) for details.