【正确答案】正确答案：①SELECT* FROM SPJ WHERE QTY BETWEEN 300 AND 500 ②SELECT Jname FROM J WHERE Jno IN(SELECT Jno FROM SPJ WHER Sno IN (SELECT Sno FROM SPJ WHERE Pno IN (SELECT Pno FROM p WHERE Color='红'))) ③SELECT Jname FROM J WHERE NOT EXISTS(SELECT* FROM SPJ SPJX WHERE Sno='S1' AND NOT EXISTS (SELECT* FROM SPJ SPJY WHERE SPJX. Pno=SPJY.Pno AND SPJY.Jno=J.Jno))；