--方式一
select *
from student
where id in(2,3,4)
--方式二
select *
from student
where id =2 or id=3 or id=4
--方式三
select *
from student
where id between 2 and 4
--方式四
select *
from student
where id>=2 and id<=4
--方式五
select *
from student
where id=2
union
select *
from student
where id=3
union
select *
from student
where id=4