PostgreSQL: Intermediate SQL HAVING Clause Exercises

This guide is specifically for PostgreSQL syntax.

Intermediate-level SQL HAVING Clause practice exercises with solutions.

Exercise 1

Question: Find departments with more than 5 employees.

SELECT department, COUNT(*) AS employee_count
FROM employees
GROUP BY department
HAVING COUNT(*) > 5;

HAVING filters groups after aggregation. WHERE filters rows before grouping. Use HAVING with aggregate functions.

Exercise 2

Question: Find products with average rating above 4.0 and at least 10 reviews.

SELECT product_id, AVG(rating) AS avg_rating, COUNT(*) AS review_count
FROM reviews
GROUP BY product_id
HAVING AVG(rating) > 4.0 AND COUNT(*) >= 10;

Multiple conditions in HAVING are combined with AND/OR just like in WHERE clause.

PostgreSQL-Specific Notes

This page covers PostgreSQL syntax. Other databases may have different syntax for similar operations.