st: Merge question

[Rohit Sonika <net@rsonika.me>]

Dear Statalist,

I have a rather odd question concerning -merge-.

I am trying to do a -merge 1:m- using two datasets. I understand that when using the 1:m command, I am asking for duplicate matches to be added below other matches. However, is it possible to, instead of creating duplicate rows, add extra columns for vars in keepusing options?

For instance, if I am trying to match two datasets based on id and year while only keeping return and exdate from the using file, the merge command would look something like this:

merge 1:m id year using "XXXX", keepusing(return exdate)

Depending on the number of additional matches per id and year, is it possible to create extra variables like return1, return2, etc. and exdate1, exdate2, etc. rather than duplicate the entire observation? Hence, if for a given id and year there are 3 matches, it should create two additional return and exdate variables (return1, return2, exdate1 and exdate2) for the two additional matches (the first match being stored in return and exdate).

Thanks a lot for your help.

Best,
Rohit
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