查询和“s002”号的同学学习的课程完全相同的其他同学的个人信息

相关表创建以及初始化

学生成绩表

  create table SC
(
  SNO   VARCHAR2(10) not null,
  CNO   VARCHAR2(10) not null,
  SCORE NUMBER(4,2)
)

学生基本信息表

create table STUDENT
(
  SNO   VARCHAR2(10) not null,
  SNAME VARCHAR2(20),
  SAGE  NUMBER(2),
  SSEX  VARCHAR2(5)
)

插入案例数据

插入sc：

insert into sc (SNO, CNO, SCORE)
values ('s001', 'c001', 78.90);

insert into sc (SNO, CNO, SCORE)
values ('s002', 'c001', 80.90);

insert into sc (SNO, CNO, SCORE)
values ('s003', 'c001', 81.90);

insert into sc (SNO, CNO, SCORE)
values ('s004', 'c001', 60.90);

insert into sc (SNO, CNO, SCORE)
values ('s001', 'c002', 82.90);

insert into sc (SNO, CNO, SCORE)
values ('s002', 'c002', 72.90);

insert into sc (SNO, CNO, SCORE)
values ('s005', 'c003', 78.90);

insert into sc (SNO, CNO, SCORE)
values ('s006', 'c004', 50.90);

insert into sc (SNO, CNO, SCORE)
values ('s007', 'c005', 81.90);

insert into sc (SNO, CNO, SCORE)
values ('s008', 'c006', 50.90);

insert into sc (SNO, CNO, SCORE)
values ('s005', 'c007', 42.90);

insert into sc (SNO, CNO, SCORE)
values ('s006', 'c008', 72.90);

insert into sc (SNO, CNO, SCORE)
values ('s005', 'c009', 52.90);

insert into sc (SNO, CNO, SCORE)
values ('s006', 'c010', 92.90);

插入student：

insert into student (SNO, SNAME, SAGE, SSEX)
values ('s001', '张三', 23, '男');

insert into student (SNO, SNAME, SAGE, SSEX)
values ('s002', '李四', 23, '男');

insert into student (SNO, SNAME, SAGE, SSEX)
values ('s003', '吴鹏', 25, '男');

insert into student (SNO, SNAME, SAGE, SSEX)
values ('s004', '琴沁', 20, '女');

insert into student (SNO, SNAME, SAGE, SSEX)
values ('s005', '王丽', 20, '女');

insert into student (SNO, SNAME, SAGE, SSEX)
values ('s006', '李波', 21, '男');

insert into student (SNO, SNAME, SAGE, SSEX)
values ('s007', '刘玉', 21, '男');

insert into student (SNO, SNAME, SAGE, SSEX)
values ('s008', '萧蓉', 21, '女');

insert into student (SNO, SNAME, SAGE, SSEX)
values ('s009', '陈萧晓', 23, '女');

insert into student (SNO, SNAME, SAGE, SSEX)
values ('s010', '陈美', 22, '女');

红色标注sql有变动的部分

第一步：找到所有和s002任意课程相同的同学

SELECT *
  FROM SC S1
  LEFT JOIN SC S2 ON S1.CNO = S2.CNO
 WHERE S1.SNO <> 's002'
   AND S2.SNO = 's002';

得到结果：

第二步 按第一步得到的结果 按sno 进行分组

SELECT SNO, COUNT(*)
  FROM (SELECT S1.SNO
          FROM SC S1
          JOIN SC S2 ON S1.CNO = S2.CNO
         WHERE S1.SNO <> 's002'
           AND S2.SNO = 's002')
 GROUP BY SNO;

第三步 对结果进行筛选，选出相同课程数和s002一样的同学

SELECT SNO, COUNT(*)
  FROM (SELECT S1.SNO
          FROM SC S1
          JOIN SC S2 ON S1.CNO = S2.CNO
         WHERE S1.SNO <> 's002'
           AND S2.SNO = 's002')
 GROUP BY SNO
HAVING COUNT(*) = (SELECT COUNT(*) FROM SC WHERE SNO = 's002');

第四步 将A学了s002所有的课程，还学了其他的课程这种情况排除

SELECT SNO, COUNT(*)
  FROM SC
 GROUP BY SNO
INTERSECT (SELECT SNO, COUNT(*)
             FROM (SELECT S1.SNO
                     FROM SC S1
                     JOIN SC S2 ON S1.CNO = S2.CNO
                    WHERE S1.SNO <> 's002'
                      AND S2.SNO = 's002')
            GROUP BY SNO
           HAVING COUNT(*) = (SELECT COUNT(*) FROM SC WHERE SNO = 's002'));

第五步 提取出学号

SELECT SNO
  FROM （SELECT SNO, COUNT(*)
  FROM SC
 GROUP BY SNO
INTERSECT (SELECT SNO, COUNT(*)
             FROM (SELECT S1.SNO
                     FROM SC S1
                     JOIN SC S2 ON S1.CNO = S2.CNO
                    WHERE S1.SNO <> 's002'
                      AND S2.SNO = 's002')
            GROUP BY SNO
           HAVING COUNT(*) = (SELECT COUNT(*) FROM SC WHERE SNO = 's002')));

第六步 得到结果

SELECT * FROM student WHERE sno IN
   (SELECT SNO
          FROM (SELECT SNO, COUNT(*)
                  FROM SC
                 GROUP BY SNO
                INTERSECT (SELECT SNO, COUNT(*)
                            FROM (SELECT S1.SNO
                                    FROM SC S1
                                    JOIN SC S2 ON S1.CNO = S2.CNO
                                   WHERE S1.SNO <> 's002'
                                     AND S2.SNO = 's002')
                           GROUP BY SNO
                          HAVING COUNT(*) = (SELECT COUNT(*)
                                              FROM SC
                                             WHERE SNO = 's002'))));

                                                                                                             

 

 

 

 

                                                                                                          学习自https://www.cnblogs.com/yin-tao/p/7880741.html