Album vs Single versions?

[Chibi_Venus]

I was wondering if someone could tell me what songs have an album version and a single version?

However, I'm curious about certain songs. For example, I know that there is a difference between the single version of "alterna" and its album version on (miss)understood. So... do you get what I'm asking about?

Which songs (that aren't completely different) have an album and a single version?

Songs that wouldn't count would be, like, "Daybreak." The album version and the single mix show an obvious difference.