Recently, I have joined Microsoft Virtual Academy and found it an amazing, free, trusted and up to date source of learning about Microsoft Cloud Technologies. Being a student of SQL Server, I was found 5 interesting tracks. You can learn some advance topics about SQL Server in a very efficient way. Not only you can learn, but you can assess your learning through self-assessments tests.
Everyone is eligible, and anyone can learn, totally free of charges.
Currently 5 SQL Server tracks with around 50 videos are available.