I watched the state of the union and they sang the happy birthday song to the holocaust survivor because it was his birthday. Has something like this ever happened before?
I'm not sure what would count as "something like this", but I'll assume you mean to ask if "Happy Birthday" was sung at any previous State of the Union address. It's always possible that it happened and was not well documented, but based on some quick searching, I'm thinking probably not. I did find that the press corps sang "Happy Birthday" to President Regan at a question-and-answer session in 1983.