为管理岗位业务培训信息建立3个表S S_IDSNSDSA S_IDSNSDSA 分别代表学号、学员姓名、所属单位、学员年龄C C_IDCN C_IDCN 分别代表课程编号、课程名称SC S_IDC_IDG S_IDC_IDG 分别代表学号、所选修的课程编号、学习成绩 要求实现如下6个处理：1查询选修课程名称为税收基础的学员信息2查询选修课程编号为C

1. 查询选修课程名称为'税收基础'的学员信息

SELECT S.S_ID, S.SN, S.SD, S.SA FROM S INNER JOIN SC ON S.S_ID = SC.S_ID INNER JOIN C ON SC.C_ID = C.C_ID WHERE C.CN = '税收基础';

2. 查询选修课程编号为'C2'的学员信息

SELECT S.S_ID, S.SN, S.SD, S.SA FROM S INNER JOIN SC ON S.S_ID = SC.S_ID INNER JOIN C ON SC.C_ID = C.C_ID WHERE C.C_ID = 'C2';

3. 查询没有选修课程编号为'C5'的学员信息

SELECT S.S_ID, S.SN, S.SD, S.SA FROM S LEFT JOIN SC ON S.S_ID = SC.S_ID AND SC.C_ID = 'C5' WHERE SC.S_ID IS NULL;

4. 查询选修全部课程的学员信息

SELECT S.S_ID, S.SN, S.SD, S.SA FROM S WHERE ( SELECT COUNT(DISTINCT C_ID) FROM SC WHERE S_ID = S.S_ID ) = (SELECT COUNT(*) FROM C);

5. 查询选修了课程的学员人数

SELECT COUNT(DISTINCT S_ID) FROM SC;

6. 查询选修课程超过5门的学员信息

SELECT S.S_ID, S.SN, S.SD, S.SA FROM S INNER JOIN SC ON S.S_ID = SC.S_ID GROUP BY S.S_ID HAVING COUNT(DISTINCT SC.C_ID) > 5