删除计算机系选修成绩不及格的学生选修记录，为什么我的执行出来0行受影响，求解惑

Question

DELETE FROM SC
WHERE Cno in(
SELECT SC.Cno FROM Student,SC
WHERE Sdept='计算机' AND Grade<60 AND Student.Sno=SC.Sno）

Answer 1

单独执行一下子查询这条语句，看看有没有符合条件的记录

SELECT SC.Cno FROM Student,SC
WHERE Sdept='计算机' AND Grade<60 AND Student.Sno=SC.Sno