There are a number of good introductory SQL resources available for free and online. There are also some paid resources which I recommend for beginners, that are very effective, and well worth expensing in my opinion.
A couple of notes:
- I haven’t used all of these resources, but they come with strong recommendations around the web or myself/my peers.
- You absolutely don’t need to use every single resource. Find a couple that work for you, and go to town.
- You can always reach out to me if you have questions. I always paste this online when people are new to asking very technical questions – it’s not meant to be snarky – it's a gentle guide on how to compose your questions and gather necessary resources in order to best give technical people the information needed to get a quick/effective response: http://www.mikeash.com/getting_answers.html
- The original Coursera