MySQL is the database management system I am most familiar with. I'm well experienced in setting up database structures from smallest to large scale.
To make my queries look their best I use indexes, stored procedures or virtual tables as needed.
I don't rely on DBALs when it comes to performance, but like to keep things in my hands so that the db performance comes with as little resource cost as possible.
My language of choice is PHP although I do miss the strong typing of Java, C# or C (it's coming to PHP 7!). The framework I have come to love is phalcon, which gives me just the right mixture of support and freedom. For smaller stuff I like to keep it framework-free and use my own scaffolding.
I have a lot of experience with TYPO3 for which I have written extensions ranging from survey or quiz software to push message delivery systems.
I don't believe in any fixations, so I'll never see myself as something like a TYPO3 or phalcon developer, I know symphony, have used zend as frameworks, for website jobs I did use wordpress, koken and what have you. For shops I used magento. The more experience, the easier to dive into new stuff.
But I've also built android mobile application clients, which means Java or Unity3D "clients", which means C#.