Serial number with conditions

kauser

Hello, 

how can i add a serial number with some conditions - 

Input Data 

F1	F2
AB	1234
AB	1234
AB	1234
AB	1234
CD	5678
CD	5678
CD	5678
CD	5678
CD	5678
CD	5678
EF	6987
EF	6987

Expected Output (with serial column) 

F1	F2	Serial
AB	1234	4
AB	1234	4
AB	1234	4
AB	1234	4
CD	5678	8
CD	5678	8
CD	5678	8
CD	5678	8
CD	5678	8
CD	5678	8
EF	6987	10
EF	6987	10

Qiu

@kauser 
I can either understand how the logic of your Serial Number, but normally we can use Tile Tool to generate the Serial Number per groups.

1115-kauser.yxmd