mysql - 如何将 2 个表连接到另一个表中

Question

这是我的表格列表:

tblsection
tblgradelevel
tblteachers

我的tblsection包含:

Section_ID | GradeID | sectionname | TeacherID

我的问题是如何在 tblsection 中链接 GradeID 和 TeacherID。

我在 tblsection 中的外键是:

Foreign key name   | Reference table            |  Column  | Reference Column
Section_GradeID    | 'database','tblgradelevel' | GradeID  |     GradeID
Section_TeacherID  |'database','tblteacher'     | TeacherID|   Teacher_ID

我使用了很多查询来执行此问题，但它不起作用。

这是我的查询:

"SELECT 
       a.Section_ID AS ID, 
       a.Sectionname AS SName,
       b.GradeLevel AS Level,
       c.TeacherID as Teach 
 FROM tblsection 
 INNER JOIN tblGradelevel b ON a.GradeID = b.GradeID";

我该怎么做？

Answer 1

**The query will generate errors due to invalid alias for the table name tblsection **
Try below query:
SELECT 
   a.Section_ID AS ID, 
   a.Sectionname AS SName,
   b.GradeLevel AS Level,
   c.TeacherID as Teach 
FROM tblsection a
INNER JOIN tblGradelevel b ON a.GradeID = b.GradeID
INNER JOIN tblteachers c   ON a.TeacherID = c.TeacherID