IIf statement

Evaluates different branch expressions depending on whether a Boolean condition is true or false.

Syntax

IIf(Logical_Expression, Value1_Expression, Value2_Expression)

Logical_Expression	A condition that evaluates to true (1) or false (0). It must be a valid Multidimensional Expressions (MDX) logical expression.
Value1_Expression	Used when the logical expression evaluates to true. Expression1 must be a valid Multidimensional Expressions (MDX) expression.
Value2_Expression	Used when the logical expression evaluates to false. Expression2 must be valid Multidimensional Expressions (MDX) expression.

In other words, the IIf function takes three arguments: IIf(<condition>, <then branch>, <else branch>).

The IIf function is not recommended for creating a set of members based on search criteria.

Returns a string "Overdue" if the due date is before today. If due date is today or after today string "On Schedule" is returned.

--example of IIf
IIf(
  DateCompare([Issue].CurrentMember.get('Due date'), "Today")<0,
  "On Schedule",
  "Overdue"
)