One of my favorite technologies are relational databases and the SQL language. I like how elleganant a solution of certain programming tasks can be using SQL - mainly graph computation. E.g., computation of neural networks in common procedural programming languages like C# and Java involves three nested loops; in SQL, it's only one loop, and the other program logic is expressed using SELECTs with JOINs. More explanation comes later.
My favorite database system is MySQL 5.0. I intentionally mention the version, because it became my favourite when it allowed to write Stored Procedures.
Through the time I created some handy general-purpose procedures and functions, which ease the developement of other procedures for MySQL.
Various SQL Implementations
Here I publish some results of my efforts in SQL:
MySQL Wishlist - feature requests
Besides that, from time to time, I also write down what do I miss in MySQL. That's quite a long list, but the most important features are:
Passing of a result set between stored procedures
sprintf()equivalent in SQL (or rather take Java's
String::format()as an inspiration)