Oracle SQL tuning

I have experience in TSQL - 5.7 years DB developement and maintenance - 5.7 years Oracle - 4years I have been doing below activities during my previous job:  Analysing and bug fixing in the developments and completing them with efficient Coding practices.  Primary skill in data analysis, data mining by writing store procedures, user defined function, views and queries in Microsoft SQL Server 2008/2014.  Plan, design, and implement application database code objects.  Build and maintain SQL scripts, indexes, and complex queries for data analysis and extraction.  Develop custom specifications and modifications for clients.  Installing fixes onto client systems and working with clients to test and promote fixes into Production systems.  Provide guidance in data preparation and migration.  Understanding the issue or the required change that has to be applied on various modules of the business intelligence system  Resolving the issues or update the system with the required changes and re-deploy the changed module.  Build and maintain SQL scripts, indexes, and complex queries for data analysis and extraction.