Dear all,

I come to you as I face a problem that sounds easy but I have stuck for good. I have two datasets to which I have a variable of a unique ID number to each (e.g. link, pair). I want to tell Stata to search if each ID number of the one variable (e.g. link) is present on the other variable (pair) and generate a dummy as an indicator.

I have searched on the Internet and tried several ways but with no success.

The last thing that maybe is important to know is that the datasets are large (191,000 and 26,000,000 obs).

Any ideas would be highly appreciated.

Thank you in advance.