Question on changing from MS SQL server to Oracle environment

[jina]

I have 3+ years of experience developing cognos BI reports using MS SQL server datasource. Now I want to work on Oracle environment. How difficult is it grasp from MS SQL server to Oracle? How long it will take time to practice to get ready to  work? why developers are using Oracle instead of MS SQL server? Any advantage?
Thanks in advance.

[FM]

Well frankly, Oracle has a lot more built in. For crying out loud, sql server won't even implement percentile by themselves!

http://download.oracle.com/docs/cd/E11882_01/server.112/e16579/aggreg.htm#i1007462

With oracle, i can do everything from NTile to percentile to moving window calculations to histograms using built in oracle features.

With sql server, i'm much more limited. Thus, oracle can take reporting to a higher level if you, as a report author, can take it.  ;)