What is the difference between ORDER BY and GROUP BY?

ORDER BY and GROUP BY are both clauses in SQL but serve different purposes. ORDER BY sorts the result set based on one or more columns, either ascending or descending, and does not change the number of rows returned. It is used when you need the data in a specific sequence. GROUP BY, on the other hand, aggregates rows that have the same values in specified columns into summary rows. It is typically used with aggregate functions like COUNT, SUM, AVG, etc., to produce a single row per group. For example, SELECT department, COUNT(*) FROM employees GROUP BY department; will return one row per department with the employee count. ORDER BY can be applied after GROUP BY to sort the aggregated results. In short, GROUP BY groups rows for aggregation; ORDER BY orders rows in the final output.