2. Joins (Combining Tables)

Try these first

1. 1.

   What does INNER JOIN do?

   Hint

   Think about how it works with overlapping data.

2. 2.

   What is a LEFT JOIN?

   Hint

   What happens to non-matched records?

3. 3.

   What does an INNER JOIN do?

   • A. Combines all records
   • B. Fetches matching records from both tables
   • C. Only shows records from the right table

   Hint

   Consider what it means for records to match.

4. 4.

   True or False: A LEFT JOIN will return only matching records from the left table.

   • True
   • False

   Hint

   Think about the nature of all records being included.

5. 5.

   Create a dataset of students and classes. Write a SQL query that lists all students and their classes, including students who are not enrolled in any classes.

   Hint

   Think of how you can keep all students in the results.

6. 6.

   You have two tables: Employees and Projects. Use a FULL OUTER JOIN to find all employees and their projects, showing employees without projects and projects without employees.

   Hint

   Consider how to capture every employee and project, regardless of their pairing.