Wellington High School have an excellent adult education program and I was lucky enough to attend a My SQL course presented by the very knowledgeable and talented Bruno Ferreira. I appreciated that whatever question you asked him he not only knew the answer but he knew the reason behind the answer.
Combining both high level best practise for designing databases and the nuts and bolts of querying them I really enjoyed learning more about SQL. Particularly fascinating to me was learning the theory behind a well organised database. Third Normal Form (3NF) is the technical term that describes the design of most databases that we use today. It was only defined in 1971 but even with the exponential advances in technology and computing power since then it is still the most commonly used method. I’ve worked in businesses where their database didn’t follow these principles correctly and it shows in many ways, making the data unreliable and hard to work with.
If you are wanting to learn more about a subject I recommend looking their courses here, they aren’t very expensive and my experience has been great. I’m very tempted by the calligraphy course!