The Original Cast Of "Fiddler On The Roof" - Fiddler On the Roof (Original Motion Picture Soundtrack) - If I Were a Rich Man

As applied in Fiddler on the Roof

Gwen Stefani & Eve - Love, Angel, Music, Baby - Rich Girl

As applied by Gwen Stefani-

Which is correct and why? (When and Why do we use subjunctive verbs?)