最简单的SQL语句

select c_name, c_stu from class where c_stu>50 or c_stu<20

楼上这个可不对了。。c_stu between 50 and 20的意思是c_stu>=20 and c_stu<=50，正好和原意相反！

用between更恰当一些
select c_name, c_stu from class where c_stu between 50 and 20