In which case is it appropriate to use the HAVING operator in SQL queries?

The HAVING operator in SQL is used to filter groups of data obtained with GROUP BY. Unlike WHERE, which filters individual rows before grouping, HAVING filters already grouped data based on aggregate functions (e.g., COUNT, SUM, AVG).

It is appropriate to use HAVING when you need to select groups that meet a certain condition. For example, to select customers whose total orders exceed a certain value:

SELECT customer_id, SUM(order_amount) AS total
FROM orders
GROUP BY customer_id
HAVING SUM(order_amount) > 1000;

Here, HAVING allows filtering customer groups by the sum of their orders.