Quiz on Data Retrieval from Multiple Tables

What is the primary purpose of SQL in the context of multiple tables?

• To delete records from a table

• To combine data from multiple tables

• To create new tables

• To update existing records

Why is combining data from multiple tables essential?

• It is necessary for relational database operations

• It simplifies database design

• It reduces data redundancy

• It speeds up data retrieval

What links tables together in a relational database?

• Views

• Foreign Key Relationships

• Indexes

• Stored Procedures

What is the primary method for combining tables based on related columns?

• Triggers

• Indexes

• Joins

• Subqueries

What does an INNER JOIN return?

• All records from both tables

• Records with matching values in both tables

• All records from the left table

• All records from the right table

What does a LEFT JOIN return?

• All records from both tables

• All records from the left table and matched records from the right table

• Only records with matching values

• Only records from the right table

What is the result of a RIGHT JOIN?

• All records from the left table

• All records from the right table and matched records from the left table

• Only records with matching values

• No records at all

What does a FULL OUTER JOIN return?

• Only records from the left table

• All records when there is a match in either table

• Records with matching values in both tables only

• Only records from the right table

What is a subquery?

• A way to update existing records

• A method to delete records

• A query nested within another query

• A query that creates a new table

What is an example use of a subquery?

• Updating customer information

• Deleting old records

• Retrieving a list of customers who placed an order in the past month

• Creating a new database