Which SQL clause is used for grouping records in a query?

• A. ORDER BY
• B. GROUP BY
• C. JOIN
• D. WHERE

Answer: (B)

The correct choice, GROUP BY, is used in SQL to group records that have the same values in specified columns into summary rows. This clause is particularly useful when performing aggregate functions such as COUNT, SUM, AVG, MAX, or MIN, as it allows you to organize and analyze data based on certain groupings. For instance, if you want to calculate the total sales for each product category, you would use GROUP BY to segment the results by category so you can apply the aggregate function to each group.

In contrast, ORDER BY is used to sort the results of a query based on one or more columns, but it does not group records. JOIN is utilized to combine rows from two or more tables based on a related column, helping to integrate data from different sources. The WHERE clause filters records based on specified conditions but does not provide any grouping functionality.

By using GROUP BY in a query, a developer can efficiently summarize and analyze data, making it a critical component for generating meaningful reports and insights from relational databases.