Design Question

[eluser]a21wat[/eluser]
I have a question for some of you long time developers. I am "re-writing" a fairly complex application using codeigniter. With that I have a couple of questions. Is it better to place ALL the SQL logic in a model or is it semantically acceptable to place some it in a controller and/or a view?

Currently I have been placing some SQL that is commonly used in a model. However, I have kept some sql requests for some of more unique queries within a view or a controller. This is the first time I am using a framework and while i understand how the application flows so to speak, I am a bit fuzzy on the "right" way to deal with the separation of SQL, Logic, and Presentation.

Thanks