It's from a song we did on The Stranger album or on 52nd Street. The song is called 'Scenes From An Italian Restaurant'. Probably hit the radio in the late 1970's, if I had to guess (and I do).
I'm a Billy Joel fan. I once had a keyboard player in my band who took lessons from Billy Joel's teacher. The guy was great.
Anyway, the song 'Piano Man' is a true story. That stuff actually happened. :-)