Query to calculate Grouwth
Hello,
I need your help to build a query to caculate a growth by Montth :
INPUT DATA with output column Growth :
Growth= Size (month) – Size(Month-1)
-- Input data in bold
Month  | Size_Go  | Growth  | 
01  | 9  | |
02  | 12  | + 3  | 
03  | 15  | +2  | 
04  | 10  | -5  | 
Regards
Djam