There is a wealth of information about SQL Server online. Absolutely hundreds of blogs, white papers, editorials, the list goes on and on. Trying to filter out the really useful, accurate (!) information from the not so useful (or just plain wrong) can be tricky. There are conflicting opinions out there which can be really confusing when you are researching a problem you are experiencing.
Below are just a few of the sites that have helped me in my day to day work immensely.
SQL Server Central
Contains an absolute wealth of knowledge on SQL Server. Articles, editorials, training and a question of the day. I use the forum on this site more than any others.
Microsoft SQL Server Forums
The official Microsoft SQL Server forum. Loads of people willing to help you out with any problems/queries you may have.
These are the guys who wrote sp_Blitz. I’d definitely recommend downloading this proc, it’s a great way of getting a quick overview of a new SQL instance. The site also has a good blog.
Download sp_WhoIsActive. A really useful proc that shows information on currently executing queries.
#SQLHelp is a great way of asking quick questions regarding SQL Server
This site provides online training for a monthly fee. It’s not expensive and the information you can get out of the courses is invaluable. However, try not to end up (like me) buying a month subscription and only doing half a course!
SQL DBA With A Beard
An old colleague of mine who is an absolute powershell whizz. If you don’t know how to use powershell, you should start learning!
If you are going to learn powershell you could probably start here powershell.com but Rob’s blog has a lot of good information specifically aimed at DBAs.
SQL Server Central and Brent Ozar’s site send out weekly newsletters which I would strongly recommend that you sign up to. I have learnt so much from both these sites.
Obviously I’ve not even scratched the surface of what is available on the internet regarding SQL Server but the sites listed are an absolute must for your bookmarks.