- SQL Zoo has some excellent interactive online tutorials, starting from the basics, it gets more interesting as you proceed: http://sqlzoo.net/wiki/SQL_Tutorial.
- A beginners course on SQL, covering the basics of databases and database manipulation, with videos, interactive exercises and challenges: http://campus.codeschool.com/courses/try-sql/contents.
- SQL Problems and Solutions is an online interactive textbook (it is possible to execute queries if you make a free account), with many examples.
- Microsoft maintains a Best Practices page for SQL Server mostly containing white papers with tips and guidelines for using SQL server.
- Pinal Dave at SQL Authority has a very informative blog about SQL Server.
- John Sansom also has a useful blog and list of SQL Server resources.
- A collection of resources from SQL Skills.
- An excellent interactive tutorial for starting to learn R. Gets you through the syntax and basics of the language quickly with with an elegant visual interface.
- Another interactive tutorial (the course is free upon making an account).
- A short introductory article.
- Quick-R has basic R tutorials and also some on statistical methods and graphs.
- A tutorial for elementary statistics with R.
- More advanced topics:
- The RDataminig website contains a wealth of resources on data mining with R, including examples, lessons (slides, videos, …), courses, as well as links more resources.
- Revolution Analytics has an introductory webinar on using R for data mining.
- Rob J. Hyndman has a blog where he writes a lotabout R and particularly forecasting using R. The topics are mostly advanced and have useful examples.
- R-bloggers is a website with news and tutorials on R.