Do you mean the SQL-Server from Microsoft ?
In this case Oracle is called more expensive.
MS-SQL runs only on Windows....Oracle on all platforms Win, Unix/Linux, Solaris, Mainframes...
Speed of the databases depends primary on hardware and the running applications.
All published benchmarks are imho only useful for the theory.
In my experience >90% of the database applications left the servermachine air to breeth.
The SQL-dialects differs in many details.
The MS-dialect is very similar to Sybase's because they have a common history.
For taking about a decision for one of them is like throwing a coin or rolling a dice with the other alternatives on the market.
The market for relational databases is rapidly changing,
Since they are stable, commercial-supported and well-known databases for no license-fee like MySQL,Interbase,Postgres and (partial) older versions of Sybase 11.0.3 for Linux, a decision isn't easy.
They run on many OSes .
For relative small workgroups using the databases, i found the Sybase Adaptive Server ANYWHERE is cheap/good valued and very,very nice.
Developer-versions for Oracle,Sybase, IBMs DB2 are free for download . (for evaluation,testing and developing, not for production environments)For MS i don't it know.
If you are beginner or/and no dependent to transactions , i recommend a MySQL. Abouts its easy syntax it is easy to learn .
(And for the most web applications very,very fast)
