Add note in "Merging Data"

[bundfussr]

I think a note in "Merging Data" regarding handling of variables which occur in both datasets would be helpful.
Assume both datasets adsl and adsl_weight have the variable STUDYID but STUDYID is not specified for by. In SAS STUDYID from adsl_weight overwrites the values of STUDYID from adsl and a note is issued. In R the output dataset will have variable STUDYID.x from adls and STUDYID.y from adsl_weight but it does not have STUDYID anymore. (The admiral function derive_vars_merged() checks this and issues an error if a variable occurs in both datasets and is not specified for by_vars.)

[mattkumar]

Thanks for the issue @bundfussr! I think this is a great note to add, that also goes hand-in-hand with other SAS-isms that have already been pointed out (@kaz462 and missing data)

Wondering if this is best covered in section 3.1.9 Merging Data or through a section devoted to admiral (e.g. future topics)? Open to all thoughts @bundfussr @kaz462

[bundfussr]

@mattkumar , I think it's best to add it to 3.1.9 Merging Data.