Bse Institute SQL Developer Interview Questions and Answers

Different types of joins include inner join, outer join, left join, and right join. Self join is when a table is joined with itself.

• Inner join: Returns rows when there is a match in both tables

• Outer join: Returns all rows when there is a match in one of the tables

• Left join: Returns all rows from the left table and the matched rows from the right table

• Right join: Returns all rows from the right table and the matched row...read more

A view is a virtual table created by a query. It can be used to simplify complex queries, provide security, and improve performance.

• Views can hide complexity by encapsulating multiple tables into a single virtual table.

• Views can restrict access to certain columns or rows, providing security.

• Views can improve performance by pre-computing joins or aggregations.

• Example: CREATE VIEW vw_employee AS SELECT emp_id, emp_name F

Optimizing SQL queries involves using indexes, minimizing data retrieval, and avoiding unnecessary joins.

• Use indexes on columns frequently used in WHERE clauses

• Minimize data retrieval by selecting only necessary columns

• Avoid unnecessary joins by using subqueries or temporary tables