Both Oracle and MS-SQL are RDBMS (Relational Database Management System),there are several differences among them.
First and foremost :
MS-SQL is a commercial product from Microsoft.
Oracle is a commercial product from Oracle
Oracle uses a SQL versions called PL/SQL (Procedural Language/SQL)
whereas MS-SQL uses T-SQL (Transact SQL)
Operating System Required :
MS-SQL -> Windows (Obviously ,since it is a Microsoft product)
Oracle - > Most Operating systems including :
Languages that support MS-SQL :
- PHP (using additional drivers)
- .NET Languages like C#,VB etc
Oracle Language Support :
C, C++, Java, COBOL, PL/SQL, Visual Basic, and C#.
All language-specific standards are supported. Developers can choose the languages in which they are most proficient or one that is most suitable for a specific task.
Find More Technical Differences between in Oracle Official Doc :
Case Study from Softex Software House :
License costs :
Note : Oracle & MS-SQL are widely used ,but you can use Oracle extensively in different platforms,but compared to MS-SQL oracle has a bit complex language(it depends from person :) ) style as they use PL/SQL .
Find Different Oracle versions answered here :
Both has good features and one can use them based on requirements.
Free versions are available with restricted features for both as a free version.
Apart from marketing strategies created by both Oracle & Microsoft for their products real challenge is to find DBAs who are familiar with any chosen DBMS.