我正在尝试构建一个包含 3 个以上数据分散在其中的表的查询

Question

Table tblSubject

subId	subName
1	Mathematics
2	English

Table tblTeachers

teacherId	teacherName
1	Jean
2	Mary

Table tblStudent

studentId	studentName
1	Edward
2	Lauren

Table tblStudentSubMap

Id	studentId	teacherId	subId
1	1	1	1
2	2	1	1
3	1	2	1
4	2	2	1
5	1	1	2
6	2	1	2
7	2	2	2

我正在尝试获得以下输出，但无法使用各种内部联接等

尝试查询：

SELECT tblsubject.subname, tblTeachers.teacherName 
  FROM tablesubject, tblteachers 
WHERE tblStudentSubMap.studentId=1

WHERE条件输入应为studentid并返回相应的学科名称和教师名称。

输出

id	tablesubject	teacherName
1	Mathematics	Jean
2	English	Mary

对于 Studentid = 1

Answer 1

有多种连接表的方法，但您可以试试我下面的代码

//Get columnName in every Table
SELECT map.Id,s.studentName,t.teacherName,sub.subName
FROM tblStudentSubMap map
LEFT JOIN tblStudent s ON s.studentID = map.studentID//Find Data with the same ID
LEFT JOIN tblTeacher t ON t.teacherID = map.teacherID//Find Data with the same ID
LEFT JOIN tblSubject sub ON sub.ID = map.subID;//Find Data with the same ID

我正在尝试构建一个包含 3 个以上数据分散在其中的表的查询

I am trying to build a query with more than 3 tables where data is scattered across

mysql

join