The music and lyrics are in the public domain in the European Union and the United States. The copyright expired in the European Union on January 1, 2017. A U.S. federal court ruled in 2016 that Warner and Chappell’s copyright claim was invalid and there was no other claim to copyright.
The one the restaurants use and the copyrighted one that families use.
Restaurant: “happy happy birthday from all of us to you. We wish it was our birthday so we could party too! Hey!”
Family/copyright: “happy birthday to you. Happy birthday to you. Happy birthday, -name-. Happy birthday to you.”
Except it is not copyrighted anynore
From Wikipedia https://en.wikipedia.org/wiki/Happy_Birthday_to_You
There’s also “This is your birthday song. It isn’t very long. Hey!”