A data analyst wants the following output: customer_name number_of_orders John Doe 388 Zhang San 234 Which statement will produce this output?

Question

Options

• ASELECT customer_name, count(order_id) AS number_of_orders
• BSELECT customer_name, count(order_id) number_of_orders
• CSELECT customer_name, (order_id) number_of_orders
• DSELECT customer_name, count(order_id)

• A
  73% (40)
• B
  16% (9)
• C
  4% (2)
• D
  7% (4)

Explanation

Option A is correct because it uses count(order_id) to count rows per customer and the AS keyword to explicitly alias the result column as number_of_orders, which matches the expected output header exactly.

• B is a common trap - omitting AS is actually valid SQL syntax (implicit aliasing works in most databases), so B would also produce the correct output in practice; however, exam questions often treat AS as required for clarity, making A the "more correct" choice.
• C is wrong because (order_id) without count() is not an aggregate function - it just references the column value, not a count of orders.
• D is wrong because without an alias, the column header would appear as count(order_id) (or similar database-specific label), not number_of_orders.

Memory tip: Think "AS = Alias Stated" - whenever you need a specific column name in the output, always use AS to make your intent explicit and unambiguous on an exam.

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