A. INSERT INTO (SELECT o.order_id, o.order_date, o.order_mode, c.customer_id, o.order_total FROM orders o, customers c
WHERE o.customer_id = c.customer_id AND c.cust_last_name='Roberts' AND
c.credit_limit=600)
VALUES (1,'10-mar-2007', 'direct', (SELECT customer_id
FROM customers
WHERE cust_last_name='Roberts' AND credit_limit=600), 1000);

B. INSERT INTO orders (order_id, order_date, order_mode,
( SELECT customer_id
FROM customers
WHERE cust_last_name='Roberts' AND credit_limit=600), order_total);
VALUES (1,'10-mar-2007', 'direct', &customer_id, 1000);

C. INSERT INTO orders
VALUES (1,'10-mar-2007', 'direct',
( SELECT customer_id
FROM customers
WHERE cust_last_name='Roberts' AND credit_limit=600), 1000);

D. INSERT INTO orders (order_id, order_date, order_mode,
( SELECT customer id
FROM customers
WHERE cust_last_name='Roberts' AND credit_limit=600), order_total);
VALUES (1,'10-mar-2007', 'direct', &customer_id, 1000);