My statement for the third to the last one:
SELECT ORDER_NUM, ORDER_DATE
FROM ORDERS, ORDER_LINE
WHERE ORDERS.ORDER_NUM = ORDER_LINE.ORDER_NUM IN
(SELECT PART_NUM
FROM ORDER_LINE, PART
WHERE ORDER_LINE.PART_NUM = PART.PART_NUM AND DESCRIPTION = 'Gas Range');
Man, hope that's right. That really had me pulling out hair.
on the subquery, you want to select the ORDER_NUM, not the PART_NUM.