Sad classical song that goes like this?

Please,don't comment if you have no idea you are wasting your time,or if you think the question is stupid. It's kinda sad/depressing classical song. its goes something like this: La la laaa,laa la la laaaa. de dee de dum. Then it kinda repeats itself. I heard it on the ending of a show on syfy and i really wanna learn it on piano.