有四张表：Student 学生表 ，Course 课程表 ，SC成绩表 ，Teacher 教师表，求SQL语句

1 查询选修课程‘3-105’且成绩在60-80之间的所有记录
2 查询成绩为85、56、88的记录
3 查询最低分大于70，且最高分小于90的学号列

1. select * from Couse as c, SC as sc where (c.id is between 3 and 105) and (sc.score is between 60 and 80);
2. select * from SC as sc where sc.score = '85' and sc.score='56' and sc.score='88';
3. select stu.id from Student as stu, SC as sc where (sc.score=(select min(sc.score) from sc))>'70';