2.1. INNER JOIN

Try these first

1. 1.

   What does INNER JOIN do in SQL?

   Hint

   Think about how it relates to two sets of data.

2. 2.

   Write a basic INNER JOIN query to retrieve names from two related tables.

   Hint

   Follow the structure of SELECT, FROM, JOIN.

3. 3.

   What is the purpose of INNER JOIN?

   • To merge tables
   • To retrieve records with matching values
   • To sort data

   Hint

   Focus on what INNER JOIN filters out.

4. 4.

   True or False: INNER JOIN will return records even if there are no matches in both tables.

   • True
   • False

   Hint

   Recall how INNER JOIN functions.

5. 5.

   Write an INNER JOIN query that retrieves names and addresses of customers who have more than 3 orders.

   Hint

   You need to group and filter based on the order count.

6. 6.

   Discuss how you would optimize an INNER JOIN query for large datasets.

   Hint

   Think about database performance best practices.