This is a part of a song's lyrics:
... (previous lines in short: I don't like you, but)
Then again it's good to get a call
Now and then, just to say hello
Have I said I hate to see you go
I hate to see you go
I don't understand the clause in bold. It has an interrogative structure, but doesn't seem to be a question, does it? Generally the song says: "Although I don't like you much, give me a call sometimes". But why does that clause have a questioning word order? What is the underlying rule for that?
I have seen changes in the normal order of the words to convey conditional meaning (for example: Had you gone, I would've gone too), or after "neither" (for example: - I don't smoke. +Neither do I), but I don't know what does it mean in the quoted lyrics above.
I'd appreciate it if someone told me for what purposes I can change the common order of declarative clauses.
Thank you in advance.