Set Operators (MDX)

Set operators perform operations on members or sets and returns a set. AtScale supports set operators in Calculated Measure formulas.

: (Range)Performs a set operation that returns a naturally ordered set beginning with the first specified member and ending with the second, and including all members between them. Both specified range members must be at the same level (if they are not, the query fails).

When using a combination of static and dynamic members, if the two members are not at the same level, the results depend on what level the query is asking for. If the query is asking for a level below the static member's level, the result is null, which is consistent with SSAS. If the query is asking for a higher level, AtScale returns null results (as opposed to SSAS, which returns an error).
Example of a 30 Period Range:

[Date].[Calendar Date].CurrentMember.Lag(29) : [Date].[Calendar Date].CurrentMember