Oracle: 

• Installation, upgrade and migration of BDDs (12c-19c)
• Installing and Patching ASM (12c-19c)
• Installing and Configuring Audit Vault 20.8
• Installation, configuration and Upgrade Oracle Enterprise Manager - Cloud Control
• Replication configuration (Physical/logical StandBy) and switch
• Backup and restore (hot, cold, logical and physical)
• TDE: data compression, encryption and masking
• ASM resource management: adding databases to ASM and vice versa.
• DB performance tuning and maintenance
• Managing access and security when assigning database roles, creating logins for users, schema privileges, table and column level permissions
• Troubleshooting incidents (AWR, logs, tkprof)
• Tuning of SQL queries to ensure response time and optimal resource consumption
• Refreshing dev/UAT/BAT/Test environments with production data

And as Oracle OBIEE Support Engineer:

• Generation of reports and interface files
• Installing, Patching and upgrading OBIEE (12)
• Deployment and maintenance of ODI agents
• Administration of OBIEE and ODI platforms