Is it possible to implement without GROUP BY?

Yes, it is possible to perform aggregations without using GROUP BY. One common approach is to use window functions, which allow you to compute aggregates over partitions of the data while still returning each row. For example, you can use SUM(amount) OVER (PARTITION BY region) to get the total sales per region for every row. Another method is to use subqueries or CTEs that compute the aggregate values separately and then join them back to the original table. However, if you need a single row per group, GROUP BY is the most straightforward and efficient way to achieve that.