Câu 20: LX0-104: CompTIA Linux+ Powered by LPI 2

Which of the following SQL queries counts the number of occurrences for each value of the field order_type in the table orders?

1. A. SELECT order_type,COUNT(*) FROM orders WHERE order_type=order_type;
2. B. SELECT order_type,COUNT(*) FROM orders GROUP BY order_type; — đáp án hiện tại
3. C. COUNT(SELECT order_type FROM orders);
4. D. SELECT COUNT(*) FROM orders ORDER BY order_type;
5. E. SELECT AUTO_COUNT FROM orders COUNT order_type;