Twice a year, the stats grad students from UBC and from SFU meet at the Harbour Centre downtown and have a one day seminar of student talks. Rather than present research, I gave a 25 minute introduction to SQL.
Specifically, it's a few slides on what SQL is, and some example queries using data from Major League Baseball's PITCHf/x data with the pitchRx package in R, and a package called sqldf. sqldf interprets queries on R data frames that are stored in local memory or in .csv files. This package is very handy for writing practice queries when you don't have access to an external database, and faster than setting up one on localhost through Wamp server.
The example queries in the talk were a showcase of common clauses in a select query, and a simple join. Below are the PDF slides and the TeX code for the presentation if you wish to use it as a template. You won't be able to compile it without the images, so be sure to comment them out first.
SQL - An Introduction in 25 Minutes, PDF Slides, TeX Code