Hi there, I am fairly new to Stata.
I am needing help in reshaping a database from long to wide. I have 3 variables pid(unique identifier), Diagnosis and DiagnosisDate, as illustrastred below.
pid Diagnosis DiagnosisDate
1 HSV2 06-02-20
1 HSV2 06-02-19
2 TV 01-01-20
2 BV 01-01-20
3 Syphillis 06-05-19
I tried using the command reshape wide Diagnosis, i(pid) j(DiagnosisDate), and i get an error message values of variable DiagnosisDate not unique within pid. I would really appreciate guidance on how i proceed to create one observation per pid instead of the existing multiple ones.

Many thanks
Ardele