1. What is difference between decode and case?
2. How will you delete duplicate records?
3. how will select first 5 records from a table?
4. what are the psedu columns?
5. Difference between delete and truncate?
6. What are the type of constraints?
7. Under which constraints the index will be created?
8. What is the difference between union and union all?
9. How will you fetch nth max salary?
10. Difference between inner join and outer join?