If your really serious about enhancing your SQL skills the following should take you from beginner to expert with time. Udemy and other online resources are nice but they will not take you to your maximum potential, only the books and official documentation will as that is where the experts get there information. The videos and tutorials are good for overviews and helping with certain scenarios but not the best resources if you want a professional high end learning path to the top.
If you want working with SQL to become extremely easy to you, you will need to start creating websites, bring traffic to those sites and implement the scaling procedures you have learned from the books below.
As if you go to a job interview and want to blow it out of the water it is to your best advantage to know for example MySQL in and out so well you make the interviewer smile inside and go yes we have found the one. You will probably see a little smirk as the interviewer is trying to hold in their smile when this happens but you will know when this occurs very easily. Upside to this is you will be very comfortable getting started on day one and the only training you will need is the current architecture and backup or non existent backup plans in place so you can get to work.
I recommend the following hardcopy books in order:
If you want working with SQL to become extremely easy to you, you will need to start creating websites, bring traffic to those sites and implement the scaling procedures you have learned from the books below.
As if you go to a job interview and want to blow it out of the water it is to your best advantage to know for example MySQL in and out so well you make the interviewer smile inside and go yes we have found the one. You will probably see a little smirk as the interviewer is trying to hold in their smile when this happens but you will know when this occurs very easily. Upside to this is you will be very comfortable getting started on day one and the only training you will need is the current architecture and backup or non existent backup plans in place so you can get to work.
I recommend the following hardcopy books in order:
MySQL: http://www.amazon.com/MySQL-Developers-Library-Paul-DuBois-e...
www.amazon.com/High-Performance-MySQL-Optimization-Replication/dp/1449314287/
http://www.amazon.com/MySQL-High-Availability-Building-Cente...
If your wanting to do Microsoft SQL Server, I recommend the following: http://www.amazon.com/Microsoft-Server-2012-Step-Developer/d...
http://www.amazon.com/Training-70-461-Querying-Microsoft-Ser...
http://www.amazon.com/Training-70-462-Administering-Microsof...