查找不在表里的数据
两张表:student eye
查找出不近视的学生姓名
思路1:NOT IN
select a.name
from student as a
where a.id not in (select b.studentid from eye as b)
思路2:LEFT JOIN
select a.name
from student as a
left join eye as b
on b.studentid is null
两张表:student eye
查找出不近视的学生姓名
思路1:NOT IN
select a.name
from student as a
where a.id not in (select b.studentid from eye as b)
思路2:LEFT JOIN
select a.name
from student as a
left join eye as b
on b.studentid is null