Thank you to all those involved in this brainstorming. I really appreciate your help. Will go on with the last suggested approach. It seems correct and fast.

Andrei

Sean, if the Data Entry department makes mistakes in finding matches, this is their problem, I don't care. My job is to create Cluster IDs based on what they provide...

Thanks, but if I insert into tbl1 the following row in addition to your rows, the approach will not work anymore:

insert into tbl1 values

(null, '10', '1');

This row should get...

Guys, thanks for the interest in solving this problem. Apologies for not giving enough information. I have it in my head and sometimes I have the wrong impression that just...