The HAVING clause is a powerful tool in SQL for filtering the results of aggregate functions. Imagine you have a table of sales data, and you want to find the departments with average sales exceeding a certain threshold. You can't use the WHERE clause directly to filter the average sales because the average is a calculated value, not a value in a specific row. This is where HAVING comes in. It allows you to apply conditions to the groups of rows after the aggregate function has calculated the values. Crucially, HAVING works *after* the GROUP BY clause, which is essential for grouping the data before applying the filter. For example, you might group sales by department and then use HAVING to filter out departments with an average sales amount below a certain value. This is a key difference from the WHERE clause, which filters individual rows before any aggregation takes place. The WHERE clause is used to filter individual rows based on their individual values, while HAVING filters groups of rows based on aggregate values. Understanding this distinction is essential for writing effective SQL queries that manipulate aggregated data.