I did a search on Google, but you can imagine what pops up with only "danny boy lyrics" as your terms. I also searched iTunes with "Danny" in the title and focusing on Alternative and Singer-Songwriter, and did come across one good song -- "Danny Boy" by Greenwich -- but although I bought it and like it, I don't think that's the one.
How would you go about finding this song? Or any song if all you have is a bit of lyric and a vague idea of a genre/kind of artist?
EDIT: Haven't found it yet but the search suggestions and community links are wonderful. Thanks