How do aggregate functions impact SQL query results?

Aggregate functions play a crucial role in SQL queries by summarizing sets of values into a single output. This capability allows users to perform calculations across a group of rows, providing insights that would be difficult to ascertain from individual data points. Common examples of aggregate functions include COUNT, SUM, AVG, MAX, and MIN, all of which generate a concise summary that represents the data.

For instance, when you use SUM to total up sales figures for a particular month, the result is a single number that gives you the overall sales for that period rather than a long list of individual sales transactions. This transformation of detailed data into summarized information enables analysts and decision-makers to quickly assess trends, averages, and totals.

In contrast, other options do not accurately describe the role of aggregate functions. While categorizing data, filtering based on conditions, and improving readability are essential aspects of SQL operations, they do not specifically define the purpose and functionality of aggregate functions.