Basic Sql interview questions

How to find highest salary
How to find nth salary
What's the use of joins
Use of aggregate operations like min Max avg count ..
How to eliminate duplicate records
Use of inner and outer joins
Left right full outer joins
Basic crud operations in SQL example using create select insert delete
Use of in and between operations
Conditional statement in SQL
Use of views trigger and procedure
Group by having example
String operations
Inner and outer queries