This
is the way I defined it in new data item.
case
when ([Month]='January') then 01
when ([Month]='February') then 02
when ([Month]='March') then 03
when ([Month]='April') then 04
when ([Month]='May') then 05
when ([Month]='June') then 06
when ([Month]='July') then 07
when ([Month]='August') then 08
when ([Month]='September') then 09
when ([Month]='October) then 10
when ([Month]='November') then 11
when ([Month]='December') then 12
else
0
end
case
when ([Month]='January') then 01
when ([Month]='February') then 02
when ([Month]='March') then 03
when ([Month]='April') then 04
when ([Month]='May') then 05
when ([Month]='June') then 06
when ([Month]='July') then 07
when ([Month]='August') then 08
when ([Month]='September') then 09
when ([Month]='October) then 10
when ([Month]='November') then 11
when ([Month]='December') then 12
else
0
end