When using GROUP BY with aggregate functions, what result is typically produced?

When using GROUP BY with aggregate functions, what result is typically produced?

• A. All groups collapsed into a single row
• B. Every original row is returned unchanged
• C. One row per group, showing subtotals
• D. Data is sorted within each group

Answer: (C)

Grouping by columns divides the data into distinct buckets based on those column values. When you apply aggregate functions in the same query, the database computes one summary value for each bucket. The result is one row per distinct group, containing the group’s values and the aggregated totals or measures for that group. For example, grouping sales data by region and summing the amount yields a single row for each region with its total sales. This is why the typical outcome is one row per group with subtotals, rather than returning every original row or simply sorting the data.

Grouping by columns divides the data into distinct buckets based on those column values. When you apply aggregate functions in the same query, the database computes one summary value for each bucket. The result is one row per distinct group, containing the group’s values and the aggregated totals or measures for that group. For example, grouping sales data by region and summing the amount yields a single row for each region with its total sales. This is why the typical outcome is one row per group with subtotals, rather than returning every original row or simply sorting the data.