Error in expression

[TomBond77]

Hi experts

I have this formula in a dimension:

=[Timestamp.autoCalendar.YearMonth]={'>=$(=Monthstart(Addmonths(Max(Timestamp.autoCalendar.YearMonth),-11)))<=$(=MonthEnd(Max(Timestamp.autoCalendar.YearMonth)))'}

It gives an error in expression although the result is shown in the information bar: 

Where is the error?

Thanks.

[rubenmarin]

H, that's not a full expression, it's just a set analysis. Set analysis it's just a filter for data, but it needs the rest of the expression to know what to do with that data, ie:

Sum({<[Timestamp.autoCalendar.YearMonth]={'>=$(=Monthstart(Addmonths(Max(Timestamp.autoCalendar.YearMonth),-11)))<=$(=MonthEnd(Max(Timestamp.autoCalendar.YearMonth)))'}>} Value)

BTW, to use operators like >= or <= the syntax is with double quotes, simple quotes is used to look for exact coincidence of strings.

[Timestamp.autoCalendar.YearMonth]={">=$(=Monthstart(Addmonths(Max(Timestamp.autoCalendar.YearMonth),-11)))<=$(=MonthEnd(Max(Timestamp.autoCalendar.YearMonth)))"}