MySQL RIGHT JOIN

MySQL Tutorial

👉 MySQL RIGHT JOIN

The RIGHT JOIN in MySQL is used to return all rows from the RIGHT table and the matching rows from the LEFT table.

👉 If there is no match, MySQL returns NULL for columns from the left table.

1️⃣ What is RIGHT JOIN?

  • Returns all records from the right table

  • Returns matched records from the left table

  • Unmatched left-table columns → NULL

📌 Also called RIGHT OUTER JOIN

2️⃣ Basic Syntax


📌 table2 is the RIGHT table (all rows included)

3️⃣ Simple Example ⭐

Table: employees

emp_id emp_name dept_id
1 Amit 10
2 Ravi 20

Table: departments

dept_id dept_name
10 HR
20 IT
30 Finance

RIGHT JOIN Query


Result

emp_name dept_name
Amit HR
Ravi IT
NULL Finance

✔ Finance appears even without employees
✔ NULL because no matching employee

4️⃣ RIGHT JOIN with WHERE Clause

⚠️ Be careful: WHERE can convert OUTER JOIN into INNER JOIN.


✔ Shows departments with no employees

5️⃣ RIGHT JOIN vs LEFT JOIN ⭐ (Interview Favorite)

Feature LEFT JOIN RIGHT JOIN
All rows from Left table Right table
NULLs appear in Right table columns Left table columns
Interchangeable ✔ Yes (by swapping tables) ✔ Yes

📌

A RIGHT JOIN B ≡ B LEFT JOIN A

6️⃣ RIGHT JOIN with Multiple Tables


📌 Use carefully—readability may suffer.

7️⃣ RIGHT JOIN vs INNER JOIN

Feature RIGHT JOIN INNER JOIN
Unmatched rows ✔ Included (right table) ❌ Excluded
NULL values ✔ Yes ❌ No
Use case Find missing relations Only matches

8️⃣ Common Mistakes ❌

❌ Confusing LEFT and RIGHT tables
❌ Using WHERE instead of ON for join condition
❌ Forgetting NULL handling
❌ Overusing RIGHT JOIN (LEFT JOIN is more readable)

📌 Interview Questions & MCQs (Very Important)

Q1. What does RIGHT JOIN return?

A) Only matching rows
B) All rows from left table
C) All rows from right table
D) Cartesian product

✅ Answer: C

Q2. RIGHT JOIN is also known as?

A) INNER JOIN
B) RIGHT OUTER JOIN
C) FULL JOIN
D) CROSS JOIN

✅ Answer: B

Q3. What happens if no match is found?

A) Row is removed
B) Error occurs
C) NULL values appear
D) Query fails

✅ Answer: C

Q4. Which join is equivalent?

A RIGHT JOIN B

A) A LEFT JOIN B
B) B LEFT JOIN A
C) A INNER JOIN B
D) B RIGHT JOIN A

✅ Answer: B

Q5. Which join is used more commonly?

A) RIGHT JOIN
B) LEFT JOIN

✅ Answer: B
(LEFT JOIN is more readable and preferred)

🔥 Real-Life Use Cases

✔ Departments without employees
✔ Customers without orders
✔ Products never sold
✔ Data completeness checks

✅ Summary

  • RIGHT JOIN returns all rows from right table

  • Unmatched left-table data becomes NULL

  • Equivalent to LEFT JOIN with swapped tables

  • Useful for finding missing relationships

  • Important for SQL exams & interviews

You may also like...