Using peek or for loop

[#1]

Hello,

I have a table with 2 ID columns ID1 and ID2.

As you can see there can be 2 ID2 for same ID1.

Column ProjectID has a numbering based on the unique ID1.

Im having trouble having a sub numbering for ID2. I don't know if I have to use peek function or a for loop.

If there are 2 ID2 for ID1, I need a new column which indicates sub rank 1,2.

If there is 1 ID2 for ID1, I need to display 1 if there are 3 ID2 grouped under ID 1, I need to have a numbering 1,2,3

Any help on this would be appreciated.

Thank you!

[#2]

Autonumber(ID2, ID1) as Counter did the trick!

Had never used earlier autonumber with 2 parameters! Thanks a lot!

[#3]

Thank you for the example. It works perfectly!

You guys are great!