PostgreSQL — Having

Basic Having

SELECT country, COUNT(*) 
FROM users 
GROUP BY country 
HAVING COUNT(*) > 10;

With Multiple Conditions

SELECT country, COUNT(*) 
FROM users 
GROUP BY country 
HAVING COUNT(*) > 10 AND COUNT(*) < 100;

With Aggregate Functions

SELECT department, AVG(salary) 
FROM employees 
GROUP BY department 
HAVING AVG(salary) > 50000;

Where vs Having

Feature	WHERE	HAVING
Filters	Individual rows	Groups
Aggregates	No	Yes
Position	Before GROUP BY	After GROUP BY

Combined

SELECT country, COUNT(*) 
FROM users 
WHERE active = true 
GROUP BY country 
HAVING COUNT(*) > 5;

Mini Practice

1. Filter groups
2. Use multiple conditions
3. Combine with WHERE
4. Compare WHERE and HAVING

Up Next

Continue with Joins — joining tables.