Control firm pick

[joon1]

Dear Madam/Sir,

My goal is to have unique control firms (gvkey2) in a particular year that match between gvkey/merge_year in dataset1 and gvkey1/year in dataset 2. It could be multiple control firms (gvkey2) matched with gvkey in dataset 1 (=gvkey1 in dataset2) in a particular year. I attach a part of dataset2 (the original file contains 8 million observations) and dataset1.

Any programming advice will be highly appreciated.

Thanks

Joon1

[HB]

Nobody is going to download those files and nobody (certainly not me) is going to understand or undertake your problem as written. 

A little bit more explanation, a working data step, an example of desired results, and things you've tried will g a long way toward helping someone help you.