RIGHT JOIN in MySQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does a RIGHT JOIN do in SQL?

A RIGHT JOIN returns all rows from the right table and the matching rows from the left table. If there is no match, the result is NULL on the left side.

beginner

How is RIGHT JOIN different from LEFT JOIN?

RIGHT JOIN returns all rows from the right table, while LEFT JOIN returns all rows from the left table. Both include matching rows from the other table and NULLs where no match exists.

beginner

Write a simple RIGHT JOIN query example.

SELECT * FROM employees RIGHT JOIN departments ON employees.department_id = departments.id; This returns all departments and their employees, including departments with no employees.

beginner

What happens if there is no matching row in the left table for a RIGHT JOIN?

The columns from the left table will contain NULL values for those rows in the result.

intermediate

Can RIGHT JOIN be replaced by LEFT JOIN?

Yes, by switching the order of the tables and using LEFT JOIN, you can get the same result as RIGHT JOIN.

What does a RIGHT JOIN return?

A All rows from the left table and matching rows from the right table

B All rows from both tables

C Only matching rows from both tables

D All rows from the right table and matching rows from the left table

RIGHT JOIN returns all rows from the right table and matching rows from the left table, filling NULLs where no match exists.

If a row in the right table has no matching row in the left table, what will the LEFT table columns show in a RIGHT JOIN?

A NULL values

B Empty strings

C The matching values

D Zeroes

When no match exists in the left table, the LEFT table columns show NULL in the result.

Which SQL keyword is used to combine rows from two tables based on a related column?

A WHERE

B SELECT

C JOIN

D GROUP BY

JOIN is used to combine rows from two or more tables based on a related column.

How can you get the same result as a RIGHT JOIN using a LEFT JOIN?

A You cannot get the same result

B Switch the order of the tables and use LEFT JOIN

C Use FULL JOIN

D Use INNER JOIN instead

Switching the order of tables and using LEFT JOIN produces the same result as RIGHT JOIN.

Which of these is true about RIGHT JOIN?

A It returns all rows from the right table

B It returns all rows from the left table

C It returns only rows with matches in both tables

D It excludes rows with NULL values

RIGHT JOIN returns all rows from the right table, regardless of matches.

Explain in your own words what a RIGHT JOIN does and give a simple example.

Think about which table's rows are always included.

How can you rewrite a RIGHT JOIN query using a LEFT JOIN? Describe the steps.

Consider swapping the tables in the FROM clause.