CodeBlanks Logo Icon CodeBlanks
Login Register

Best sellers

Find the best-selling product with HAVING.

Best seller

To find the best-selling product you use GROUP BY product and HAVING.

SELECT product, SUM(amount) AS total
FROM sales
GROUP BY product
HAVING SUM(amount) > 1000;

This query returns products selling over 1000.

product, SUM(amount) AS total is selected from sales. Rows are grouped by product; aggregate functions are computed per group. HAVING SUM(amount) > 1000 runs after grouping and drops groups that fail the condition.

Best seller — details

HAVING runs after groups are formed. ORDER BY can put the highest total first.

For example, ORDER BY total DESC LIMIT 5 returns the five best-selling products.

Practice Best seller

Find products with totals over 1000 using HAVING SUM(amount) > 1000.

Starter code

query.sql
-- best seller
SELECT product, SUM(amount) AS total
FROM sales
GROUP BY product

Sample solution

query.sql
SELECT product, SUM(amount) AS total
FROM sales
GROUP BY product
HAVING SUM(amount) > 1000;

Expected output

product  total
Laptop   3500
Telefon  2100

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 How do you find the best seller?

  • WHERE + COUNT
  • DISTINCT
  • GROUP BY + HAVING Correct answer
  • JOIN

Explanation: Group by product and filter with HAVING.

2 Add HAVING

Question 
SELECT product, SUM(amount) AS total
FROM sales
GROUP BY product
____ SUM(amount) > 1000;
Answer 
SELECT product, SUM(amount) AS total
FROM sales
GROUP BY product
HAVING SUM(amount) > 1000;

Explanation: HAVING SUM(amount) > 1000 keeps products whose total sales exceed 1000.

3 Best sellers: match the terms

Term Meaning
GROUP BY group
HAVING filter
SUM sum
ORDER BY sort

All lessons in Intermediate

1 INNER JOIN in depth

  1. INNER JOIN logic
  2. Choosing the join column
  3. Three-table INNER JOIN
  4. Self JOIN
  5. Filtering joins
  6. Summary - INNER JOIN

2 LEFT and RIGHT JOIN

  1. LEFT JOIN
  2. RIGHT JOIN
  3. Unmatched rows
  4. JOINs with NULL
  5. LEFT vs RIGHT
  6. Summary - LEFT and RIGHT JOIN

3 FULL and CROSS JOIN

  1. FULL OUTER JOIN
  2. CROSS JOIN
  3. When to CROSS JOIN
  4. Comma JOIN
  5. Choosing a JOIN type
  6. Summary - FULL and CROSS JOIN

4 Project: Library database

  1. Library design
  2. Books and authors
  3. List loans with LEFT JOIN
  4. Find overdue loans
  5. Member summary

5 GROUP BY

  1. What is GROUP BY?
  2. Single-column grouping
  3. Multi-column grouping
  4. GROUP BY with aggregates
  5. Ordering grouped results
  6. Summary - GROUP BY

6 HAVING

  1. What is HAVING?
  2. HAVING vs WHERE
  3. HAVING with aggregates
  4. Multiple conditions
  5. HAVING with aliases
  6. Summary - HAVING

7 Aggregate functions

  1. COUNT
  2. SUM
  3. AVG
  4. MIN and MAX
  5. NULL and aggregates
  6. Summary - Aggregates

8 Project: Sales report

  1. Sales design
  2. Daily revenue
  3. Best sellers
  4. Customer segments
  5. Low performers

9 Subquery

  1. What is a subquery?
  2. Scalar subquery
  3. Subquery with IN
  4. ANY and ALL
  5. Correlated subquery
  6. Summary - Subquery

10 EXISTS

  1. What is EXISTS?
  2. NOT EXISTS
  3. EXISTS vs IN
  4. EXISTS performance
  5. Multiple EXISTS
  6. Summary - EXISTS

11 UNION and INTERSECT

  1. UNION
  2. UNION ALL
  3. INTERSECT
  4. EXCEPT
  5. Set rules
  6. Summary - UNION and INTERSECT

12 CASE

  1. What is CASE?
  2. Searched CASE
  3. Simple CASE
  4. The ELSE branch
  5. CASE with aggregates
  6. Summary - CASE

13 VIEW

  1. What is a VIEW?
  2. CREATE VIEW
  3. Querying a VIEW
  4. DROP VIEW
  5. Updatable VIEWs
  6. Summary - VIEW

14 INDEX basics

  1. What is an INDEX?
  2. CREATE INDEX
  3. Composite INDEX
  4. DROP INDEX
  5. When to index
  6. Summary - INDEX

15 Project: Blog database

  1. Blog design
  2. Post list
  3. Tag search
  4. Author stats
  5. Search index

16 Normalization

  1. What is normalization?
  2. First normal form
  3. Second normal form
  4. Third normal form
  5. BCNF
  6. Summary - Normalization

17 Data integrity

  1. What is integrity?
  2. Entity integrity
  3. Referential integrity
  4. Domain integrity
  5. Integrity with triggers
  6. Summary - Data integrity

18 Transaction basics

  1. What is a transaction?
  2. BEGIN and COMMIT
  3. ROLLBACK
  4. SAVEPOINT
  5. ACID
  6. Summary - Transaction

19 ALTER and DROP

  1. ALTER TABLE
  2. Adding a column
  3. Dropping a column
  4. Changing a column type
  5. DROP TABLE
  6. Summary - ALTER and DROP

20 Intermediate final

  1. Multi-JOIN report
  2. Aggregate analysis
  3. Subquery challenge
  4. Transaction scenario