What the SQL?
Over the past few years there's been a rennaisance in data storage which has been focused on making non-relational object persistence easier. This maps well to the needs of lots of mobile and web applications.
While another tool in the toolbox is a great thing, new programmers are starting to forget the old ways. Widespread use of ActiveRecord style ORMs in Rails and Django means that many developers who use a traditional RDBMS might not even fully grasp the way that data gets queried.
Inspired by a great blog post about a simple SQL interview question set, I decided to create an interactive version. Hopefully this will reaffirm or jog the memory of experienced programmers who perhaps do not deal with SQL anymore, and start novices down the path of picking up SQL as a skill.