分析:学习
1,先查询出01号同窗学习的课程spa
SELECT C FROM sc WHERE S='01'
2,查询学习该相关课程的同窗编号code
SELECT S FROM sc WHERE C in (SELECT C FROM sc WHERE S='01')
能够看到,咱们分别查询了3次,因此出现多个结果,由于是or关系,因此每一个选择了一、二、3课程的同窗都所有取出,blog
3,如今须要将出现次数为3的编号取出class
SELECT S FROM sc WHERE C in (SELECT C FROM sc WHERE S='01') GROUP BY S HAVING COUNT(S) =3
看到编号为一、二、三、4的同窗选了与01号同窗一致的课程im
4,与student表进行连表查询,取出相关信息查询
SELECT a.* FROM student a LEFT JOIN sc b ON a.S = b.S WHERE b.S in ( SELECT S FROM sc WHERE C in (SELECT C FROM sc WHERE S='01') GROUP BY S HAVING COUNT(S) =3) GROUP BY a.S