I personally feel that if it's running the the database, regardless if it's called from say C# code, it's ok here. I don't think SQL belongs on stack overflow, because it doesn't work like other languages do, and if you try to write SQL like you would try to write in another language you'll end up doing it wrong and your code will perform worse, assuming it even works.
Also I voted for this site in the first place because I feel that database administration falls somewhere in between programming and server administration, and sometimes answers can apply in both programming and administration, so neither StackOverlow nor ServerFault could be seen as the right place for a database question.
Feel free to ask SQL, Administration, and Tuning questions here.
Like @Gary said in his comment to this answer I too committed to this site because I wanted a place where I could go to ask questions where Database guru's hung out.
Update: I would like to add to my statement as a Pro Tem Moderator for Unix SE. All of our questions, would have been on-topic on one of SO, SF, SU, AU, or even Programmers. We simply focussed on what we would allow. I also advise against falling into a trap of defining yourself by what you aren't. We had the initial problem of people wanting to say if it's crossplatform (with windows) it's offtopic. Do not define yourself by what you aren't Unix is not windows, but just because it works on windows doesn't mean it's not unix. Or in DBA, just because it's C# doesn't mean it's not databases, just because it's Programming, doesn't mean it's not ontopic. We also allow shell, and some Unix C API questions on our site, both of which overlap highly on SO, but the former is probably the most common type of question we get.