SQL
Filtering Aggregated Results with SQL HAVING Clause
Understand the critical distinction between WHERE and HAVING clauses to effectively filter groups of data based on aggregate functions, refining your analytical queries.
SELECT category, COUNT(product_id) AS total_products,
AVG(price) AS average_price
FROM products
GROUP BY category
HAVING COUNT(product_id) > 5 AND AVG(price) > 50.00
ORDER BY total_products DESC;
How it works: This snippet illustrates the use of the `HAVING` clause to filter aggregated results. While the `WHERE` clause filters individual rows *before* aggregation, the `HAVING` clause filters groups of rows *after* they have been aggregated by `GROUP BY`. In this example, it selects categories that have more than 5 products *and* an average price greater than 50. This is crucial for analytical queries where you need to apply conditions to the results of aggregate functions.