How INNER, LEFT, RIGTH and OUTER JOIN works is a common question and not always easy to remember. Here you can see the different joins visually and through interaction
This is good timing, as my dad (a SQL novice) is going to be taking a course on SQL soon and references like would really help, any others I should know about?
[+] [-] jlewallen|12 years ago|reply
[+] [-] spathon|12 years ago|reply