一．查询
二．修改
修改 多个元组的值 6 所有 学生 年龄增加 1岁.note
update student
set sage=sage+1
带子查询的修改语句 7.note
update sc
set grade=0
where 'cs'=
( select Sdept
from student
where student.sno=sc.sno
)
update sc
set grade=0
where 'cs' in
( select Sdept
from student
where student.sno=sc.sno
)