MDX Function and Operator Reference - Professional SQL Server Analysis Services 2005 with MDX - page 1113

Against this set of tuples (which we will call Set1) and associated values,
the following is true:
Rank ([Product].[Leather Pants], Set1) is 2.
Rank ([Product].[Leather Bags], Set1, [Measures]
.[Sales]) is 3 (tied with leather gloves).
Rank ([Product].[Leather Skirts], Set1, [Measures]
.[Units]) is 5 in AS2000 (the tie with leather pants is not noticed). In
AS2005, it is 1 (tied for first place when sorted in ascending order).
Note that the .Item () and Subset () functions use a zero-based index; the
rank of Set.Item (0) is 1.
See also: .Item (), Subset (), Head (), Tail ()
RollupChildren ( member , string expression ) Returns: number Extension:
AS2005, AS2000
This function is used to return the value generated by rolling up the chil-
dren of a specified parent member using the specified unary operator.
The string expression is evaluated once per child of member. You can
use a constant string value for the expression, as well as a string value
that changes with each member. The first (or only) unary operator may
be one of +, − , ~, or a number, while subsequent operators may be one
of +, − , ⊛ , /, ~ or a number. When a number is used, it is a weighting
value; the effect is to multiply the cell value related to the child member
by the number, and add it to the accumulating rollup value. Frequently, a
reference to a member property ([Dimension].CurrentMember.Properties
("Some Property")) will be the string expression. You may also use a
string expression based on a property. For example, the following ex-
pression will create the positive sum of all children that would ordinarily
be subtracted from the sum:
iif ([Accounts].CurrentMember.Properties
("UNARY_OPERATOR") <> "-",
"~",
"-"
)