Merge, update replace : Keeping the missing value from using.

[Christophe Misner]

Hi everyone,

When you use merge with the update replace option, all values from master variables are replaced by nonmissing values from using.
I would like to know if there is an alternative to replace by missing values in case the variable is nonmissing in master and missing in using.

For instance:

Var1 = 5 (Master)
Var1 = . (Using)
Var1 = . (Result after merge)

Thank you very much.
Christophe

[Bruce Weaver]

Hello Christophe Misner. I do not see any straightforward way to do that via -merge-. You might have better luck using -frlink- to link two data frames followed by -frget-. I've only taken a quick look, but I think some of the examples here might be instructive.

• https://www.stata.com/manuals/dfrlink.pdf#dfrlink

Cheers,
Bruce

[Christophe Misner]

Great, thank you Bruce Weaver for your answer.