action feature version location count ?difference? A f1 v1 WA 120 0 A f1 v1 OR 110 10 A f1 v1 CA 115 5 B f1 v1 AZ 120 0 A f1 v2 WA 14 1 A f1 v2 OR 10 5 B f1 v2 AZ 15 0 I got a table of info above: action, feature, version, location, and count.  Could anyone help me to find the last column "difference" here?   A group is identified by same feature and version combination. so in the example table, the first four rows(f1+v1) are one group, and the last three rows(f1+v2) are the second group.  within each group, difference = count B - count A.    for example: row1, difference = count (B, f1, v1, AZ) - count (A, f1,v1,WA) = 120-120=0 row2, difference = count (B, f1, v1, AZ) - count (A, f1,v1,OR) = 120-110=10 difference of countB itself is 0. ... View more