📝 What You’ll Learn

• What COUNT() does
• Basic and advanced syntax
• Real-world examples
• How to use COUNT() with GROUP BY and WHERE

📌 What Is COUNT?

The COUNT() function returns the number of rows that match a specific condition.

It is commonly used to:

• Count all rows
• Count non-null values in a column
• Get totals for grouped data

🧱 Basic Syntax

Count all rows (including NULLs)

SELECT COUNT(*) FROM table_name;

Count non-null values in a column

SELECT COUNT(column_name) FROM table_name;

🧪 Example: Total Users

SELECT COUNT(*) AS total_users
FROM users;

🧪 Example: Count Users with Email

SELECT COUNT(email) AS users_with_email
FROM users;

✅ This excludes rows where email is NULL.

📊 Example with GROUP BY

Count users per country

SELECT country, COUNT(*) AS user_count
FROM users
GROUP BY country;

📌 Example with WHERE

Count users from USA

SELECT COUNT(*) AS usa_users
FROM users
WHERE country = 'USA';

📘 Recap

• COUNT(*) counts all rows, including those with NULLs
• COUNT(column) counts non-null values only
• Combine with GROUP BY for grouped totals
• Add WHERE to count conditionally