At the supported service pack level, Mainstream Support includes:
Incident support (no-charge incident support, paid incident support, and support charged on an hourly basis)
Security update support
The ability to request non-security hotfixes through CSS or the Product Team
At the supported service pack level, Extended Support includes:
Paid support
Security update support at no additional cost
Non-security related hotfix support requires a separate Extended Hotfix Support Agreement to be purchased (per-fix fees also apply)
For SQL2008/2008R2 in Azure, this is free! (if you have Software Assurance).
Customers with active Software Assurance or subscription licenses can purchase Extended Security Updates for approximately 75% of the on-premises license cost annually. (1)
For SQL2008/2008R2 this is available for three years after end of Extended Support (ending 12-Jul-2022)
This no longer be available. Replaced by Extended Security Updates.
Extends Support for a further 6 years
Only available if you have Software Assurance