It did this with Nicki Minaj - I bought Starships then bought her album and they were seperated. The fix I found was to go into the info of the album playlist by right clicking > get info and take note of what is in the boxes. Then go into the info of the single track and change the Artist field, Album Artist field and the Album field to the same as that of the album.
Hope that helps
This is probably the most poorly handled option on the iTunes Store. I have had several albums messed up this way, either from purchasing a single track, an actual single, or and EP that is eligible to the complete my album upgrade. To have an option to complete an album, only to have it half completed and to have to manually adjust metadata is something that Apple should be ashamed of. I have sent a question into the iTunes support only to never hear back from them on this issue... I'd almost rather pay full price just to save the headache they cause, but of course that's what they want.
And just to add to that one... I recently pre purchased the new Tragically Hip album. Upon purchase I was awarded with an advanced track, great! Only when the day of release came, guess what. iTunes screwed it up! They couldn't even handle their own pre purchase, and when editing the normal metadata like album, track number and band name it still wouldn't show together. I ended up deleting both the album and the single, and reflow loading the album again just I have it listed together. How's that for messed up? I don't think I'm going to preorder any more albums...
I have this exact same question / issue too and it is definitely something I would LOVE to see Apple fix ASAP. It is especially important to me because so many popular artists release Singles (as Single Albums) weeks or even months in advance of their full album coming out. When I have the choice, I ALWAYS prefer to buy a single song from the album it is on (in case I like the song a lot and want to check out more from that artist) - however, this is often not possible due to the "Single Album" phenomenon. Sidenote: could you just freakin' get rid of Single Albums altogether (when there is an associated real album)? They clutter up the See All Albums view horribly - at least give us a filter or something for the real-deal studio albums vs all the junk.
While it is great that I get "credit" for my purchase from the Single Album towards the real Album (thanks for that Apple), I personally have a strong preference to then see the original single as part of the album instead of as a stand-alone. It's just cleaner organization-wise, easier from a usability standpoint (you can actually listen to the whole album you bought using the album filter!), etc. It would at least be nice to have the choice to "convert" the original single to the Album version, if Apple is concerned about forcing the change (I personally would be happy with a forced change, but if given a choice would always convert).
Please fix this!!!
-Bought Calvin Harris, "Feel So Close (Radio Edit)" back in March '12 (I think it was released in August '11) for $1.29
-Completed My Album by buying "18 Months" album for $8.70 recently (released Oct 30, 2012)
-Was happy to pay $8.70 instead of $9.99 (got full credit for the $1.29 I spent on the single) - good job Apple
-Am now frustrated that "Feel So Close (Radio Edit)" has different Album info, different Album cover art etc - BAD job Apple
Would love to hear that this is going to be addressed soon - hopefully with a retroactive converter tool too??
PS I realize I could manually adjust the metadata for the track to make it match, but I HATE the idea of doing that. Very clunky solve and I personally would be worried that I missed something or didn't "fully" change everything, the underlying file is not exactly what I would have gotten from the full album version, etc.