SolveWithSQL

Difficulty: Beginner
Estimated time: 5–10 minutes
SQL concepts: COUNT(), counting rows, aggregates
Goal: Learn how to count records reliably (a daily SQL task).

The Scenario

A product manager asks a simple question:

“How many products are in our catalog?”

You don’t need to list every product—just return the total number of rows in the products table.

Database Table

products

column_name	type	description
product_id	INTEGER	Unique product ID
name	TEXT	Product name
category	TEXT	Product category
price	DECIMAL	Product price
stock_qty	INTEGER	Units in stock
created_at	TIMESTAMP	When the product was created

Sample Data (for context)

product_id	name	category	price
101	Wireless Mouse	Accessories	24.99
102	Mechanical Keyboard	Accessories	89.00
103	27-inch Monitor	Displays	229.99
104	USB-C Hub	Accessories	34.50
105	Laptop Stand	Workspace	39.99

Your Task

Write a SQL query that returns one number:

• The total count of products in the products table

Expected Output

Your result should look like this:

total_products
5

(The exact number depends on the data in your table. With the sample data above, it would be 5.)

Constraints

• Use COUNT() to count rows
• Return a single row with a single column
• Name the output column: total_products

Explanation

• COUNT(*) counts every row in the table.
• AS total_products renames the output column so the result is easy to understand.
• This is a standard pattern used in analytics, reporting, and debugging.

Common Mistakes

1. Counting a nullable column
   SELECT COUNT(stock_qty) FROM products; -- may undercount if NULL values exist
2. Forgetting the alias
   • The query works, but the column name may be unclear.
3. Expecting multiple rows
   • Aggregate functions like COUNT() return a single result unless used with GROUP BY.

Optional Extension (Mini Bonus)

Try answering:

1. How many products are in the Accessories category?
2. How many products have a price greater than 50?

(You can combine WHERE with COUNT().)

Next Challenge

Beginner Challenge #5: Remove Duplicates with DISTINCT

🔗 View reference solution on GitHub
(After you’ve tried the challenge)

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