Mysql 如何从表中检索学生信息？

如何编写查询以从所有表中获取学生S1的信息。 例如，学生S1参加体育活动的姓名、教师姓名谁教学生S1、学生S1家长信息。在这里，学生、教师、家长表中的id是主键。stud_id、teacher_id、sports_id是外键，指学生、教师、运动表主键。

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请帮助我从表格中获取学生S1的记录。提前谢谢

以下是解决方案：

student table   teacher table    sports table     parents table
---------     --------------     ------------      ---------------
id  name        id  name        id  name           id    stud_id  fathername   mothername
------------   ------------    ------------        -----------------------------------------
1    S1           1     T1         1    SP1         1       1       xxxxxx       yyyyyyy
2    S2           2     T2         2    SP2         2      2        abc          aaa    
3    S3           3     T3         3    SP3 

student_teacher table               student_sports table
id    stud_id     teacher_id       id      sutd_id    sports_id
------------------------------     ------------------------------
1      1            1               1        1          1
2      1            2               2        1          2
3      1            3               3        1          3
4      2            2               4        3          2
5      2            3               5        3          3

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您可以简单地使用where子句：

select st.name as Student, t.name as teacher, sp.name as sports, p.fathername,p.mothername from student st,teacher t,sports sp,parents p,student_teacher s_t,student_sports s_s where s_t.stud_id=st.id and s_t.teacher_id=t.id and p.stud_id=st.id and s_s.stud_id=st.id;

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您需要将

student\u-teacher

和

student\u-sports

表组合在一起。没有办法把哪个老师教哪个学生做某项运动的结果结合起来。我们所知道的是，学生1参加了体育1、2和3，并由1、2和3老师授课。我们不知道哪位老师参加了哪项运动。你应该有这个：

select S.name, T.name, SS.name, P.fathername, P.mothername 
from student S, teacher T, sports SS, parents P,student_teacher ST, student_sports SSP 
where S.id = ST.stud_id and T.id = ST.teacher_id and
S.id = SSP.stud_id and SS.id = SSP.sports_id and
S.id = P.stud_id

完成后，您可以使用连接获取所有数据：

student_sports_teacher table
+----+---------+-----------+------------+
| id | stud_id | sports_id | teacher_id |
+----+---------+-----------+------------+
|  1 |       1 |         1 |          1 |
|  2 |       1 |         2 |          2 |
|  3 |       1 |         3 |          3 |
|  4 |       2 |         1 |          2 |
|  5 |       2 |         2 |          3 |
+----+---------+-----------+------------+

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可以使用内部联接

SELECT * FROM student s
LEFT JOIN parents p ON s.id = p.stud_id
LEFT JOIN student_sports_teacher sst ON sst.stud_id = s.id
LEFT JOIN sports sp ON sp.id = sst.sports_id
LEFT JOIN teacher t ON t.id = sst.teacher_id

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不需要使用左连接。OP使用外键，因此您不会有任何孤立记录。这只是一个习惯，我总是指定联接类型。

     select st.name as Student, t.name as teacher, sp.name as sports, 
          p.fathername,p.mothername 
     from student st
     Inner join student_teacher as st on st s_t.stud_id=st.id 
     Inner join teacher t on s_t.teacher_id=t.id 
     Inner join parents p on p.stud_id=st.id 
     Inner join student_sports ss on  ss.stud_id=st.id;