What is required for every column when computing aggregates in a query?

When computing aggregates in a query, every column included must either be an aggregate function or specified in a GROUP BY clause. This is essential because aggregate functions compute a single result from multiple rows of data (such as SUM, COUNT, or AVG), while the GROUP BY clause defines how the rows are grouped together before the aggregates are computed. This ensures that the result set contains meaningful summaries of the data, allowing for analysis of specific segments rather than just a flat total.

For example, if you are calculating the total sales grouped by region, you must include the region column in the GROUP BY clause while using aggregate functions to calculate values like total sales for each region. This way, you maintain clarity in the data and ensure that the aggregates are correctly aligned with their respective groups.