Take what you learned in SQL Patterns: Basic Techniques and build on it. This course covers a series of intermediate-level techniques that you can use to make your reports more flexible, faster, and less intrusive to other users of your system.

This course assumes that you are already familiar with basic SQL concepts, keywords, and techniques for finding and fixing erros in your queries. (If you're not, start with SQL Patterns: Basic Techniques.)

Consider combining this course with an hour of consulting time for only $75 more--there's really nothing like being able to work for a while on a problem then ask some pointed questions that apply to what you need to do yourself.

Another option to consider is following up this course with a workshop session (you get to set the topics and ask for help on problems you've been struggling with). Following up self-paced training with a workshop is highly productive, and discounts on workshops are available to purchasers of SQL Patterns courses.