Having focused on front end development up until now, I'm finally getting round to my ambition to delve into a back end language, probably PHP, although the frameworks for Ruby/Python seem appealing too.
I've already got a pretty decent handle on Python, and jumped into the (official) Django tutorial but got stumped pretty quick by the talk of databases. Same applied when I had a quick look at the Rails tutorial. It quickly struck me that the problem I'm having is that I know nothing about databases.
With that said, it seems I might be better off starting with PHP with a view to learning MySQL in conjunction with it. Are there any recommended books/websites/guides that offer a good solid foundation on both PHP and SQL, or failing that, a decent (comprehensive) primer on SQL?