Keith,
here's my guess why the search failed: Neither 'be a farmer' nor 'be a farmer*' fail for a search but in both cases the song you are looking for is not among the first fifty hits, for there are too many songs that have the words 'be' 'a' and 'farmer' in them at some place in the song.

Go for a phrase this way: '[be a farmer*]' and you'll get only very few hits including the correct song.

Wolfgang