Same Fields SQL

[NewtonLN]

I need help with a query/subquery:
I’m trying to find duplicate patients, where 3 fields are the same:
PATIENTNAME=PATIENTNAME AND BIRTHDATE=BIRTHDATE AND DIAGNOSEDATE=DIAGNOSEDATE , like these:

1. John, 01/01/2001, 01/09/2010
2. John, 01/01/2001, 01/09/2010
3. Doe, 09/01/2001, 01/01/2015
4. Doe, 09/01/2001, 01/01/2015
   and so on.
   Thank you, very much!

[mariosv]

I think it’s explained in:

Finding duplicate values in a SQL table