Calculate difference between two month

Hi Anonymous

It would be much easier if you had the dates in another format. How about a new column like this:

NewColMonthDiff=
VAR _StartMonthNum=SWITCH( LEFT(Table1[StartMonth],3),
                                 "Jan", 1,
                                 "Feb",2,
                                  ...
                                 "Dec",12)
VAR _EndMonthNum=SWITCH( LEFT(Table1[EndMonth],3),
                                 "Jan", 1,
                                 "Feb",2,
                                  ...
                                 "Dec",12)
VAR _StartYear=RIGHT(Table1[StartMonth],4)
VAR _EndYear  =RIGHT(Table1[EndMonth],4)
RETURN
1+ (_Endyear - _StartYear)*12 + _EndMonthNum - _StartMonthNum

where you would have to complete the two SWITCH statements with all the months and their numbers (where I've placed the '...')