A frequent question I get is what the new stuff is in some version of SQL Server. And, sure, Microsoft has a very exhaustive "what's new" section for each version of SQL Server. This is lost after some 5-10 years, though. The purpose of this page is to list all news on one page and keep a longer trail than 5-10 years. Focus is the SQL engine, on-premise.
Each version adds a new database compatibility level (the concept of database compatibility level was introduced in 7.0). Starting with SQL Server 2014 this can also affect performance, for instance enabling new functionality in the optimizer as well as controlling the Cardinality Estimation version used.
SQL Server 2017
https://docs.microsoft.com/en-us/sql/sql-server/what-s-new-in-sql-server-2017
SQL Server 2016
https://docs.microsoft.com/en-us/sql/database-engine/whats-new-in-sql-server-2016
SQL Server 2014
https://docs.microsoft.com/en-in/SQL/database-engine/whats-new-in-sql-server-2016?view=sql-server-2014
SQL Server 2012
Project name Denali. Version 11.From memory...
Project name Kilimanjaro. Version 10.5.
To be done
Project name Katmai. Version 10.0.
To be done
Project name Yukon. Version 9.0.
Project name Shiloh. Version 8.0.
Project name Sphinx
SQL Server 6.0, 1995
Project name SQL95OS/2 and Windows NT
I'm treating these versions the same, even though there are 4.2a, 4.2b (both OS/2) and 4.21a (Windows NT). Below is from memory.
SQL Server 1.1, 1990
Project name Pietro. OS/2
From memory...
Project name Filipi. OS/2
This was the first release of Microsoft SQL Server. There were earlier releases from Sybase, but this list is for Microsoft SQL Server, running on either OS/2 or Windows.