MDX Function and Operator Reference - Professional SQL Server Analysis Services 2005 with MDX - page 1065

If one or more children of a member to be drilled down into immedi-
ately follows a parent in set, then that parent will not be drilled down
into.
DrillDownLevelBottom ( set , index [,[ level ] [, numeric expression ]])
Returns: set
Standard
Similarly to DrillDownLevel () and DrillDownLevelTop (), this function
drills down through all members in the set that are at the specified level ,
if the level is provided (or the lowest level of members that are present in
the set if level is not provided). However, instead of returning all children,
this function returns only the bottom index members or tuples. The set
can be of arbitrary dimensionality. The ranking is determined through the
numeric expression , if one is provided, or through the values of cells
found in the default context when the set is evaluated, if the numeric ex-
pression is left out. Figure A-14 illustrates the behavior of
DrillDownLevelBottom ().
Figure A-14: DrillDownLevelBottom ().
If one or more children of a member to be drilled down on immedi-
ately follows a parent in the set, then that parent will not be drilled
down into.
DrillDownLevelTop ( set , index [, [ level ] [, numeric expression ]] )
Returns: set Standard