What is the purpose of the HAVING operator in SQL?

The HAVING operator in SQL is used to filter groups of rows created by the GROUP BY operator. Unlike WHERE, which filters individual rows before grouping, HAVING applies to the aggregated results of groups after they are created.

Main use cases:

• Filtering groups based on aggregated values (for example, selecting only groups with a total income of more than 1000).
• Filtering groups where the number of elements meets a certain condition (for example, selecting groups containing more than 5 orders).

Example of a query structure with USING:

-- Select the department where the total salary exceeds 100,000
SELECT
    department,
    SUM(salary) AS total_salary
FROM
    employees
GROUP BY
    department
HAVING
    SUM(salary) > 100000;