A、演绎推理 B、直接推理 C、间接推理 D、归纳推理
A、SELECT ord_id, cust_id, ord_total FROM orders, customers WHERE cust_name='Martin' AND ord_date IN ('18-JUL-2000','21-JUL-2000'); B、SELECT ord_id, cust_id, ord_total FROM orders WHERE ord_date IN (SELECT ord_date FROM orders WHERE cust_id = (SELECT cust_id FROM customers WHERE cust_name = 'Martin')); C、SELECT ord_id, cust_id, ord_total FROM orders WHERE ord_date IN (SELECT ord_date FROM orders, customers WHERE cust_name = 'Martin'); D、SELECT ord_id, cust_id, ord_total FROMorders WHERE cust_id IN (SELECT cust_id FROM customers WHERE cust_name = 'Martin');