IIf statement

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

Syntax

IIf(Logical_Expression, Expression1, Expression2)

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