where
select sname,sdept,sage
from student
where ssex = '男' or ssex = '女' and sage not between 20 and 23select distinct sno
from sc
where cno between '1'and '2'
like
use stu
select *
from student
where sdept = 'CS' or sdept = 'MA' and sname like '张%'select *
from course
where cname like 'DB\_%k_i__' escape '\'
