查询相关表

Question

我目前正在尝试运行一个查询，它将显示所有相互关联的表。我没有制作桌子的设计。所以我在制作时遇到了一些麻烦：目前还不清楚office_hours表与schedule表的关系如何？总体而言，如何正确显示所有通过查询关联的表？

SELECT * 
FROM schedule 
INNER JOIN semester ON schedule.semester_id = semester.id 
INNER JOIN office_hours ON office_hours.id = schedule.??? 

Answer 1

我认为ID从表schedule只是一个auto_increment柱并加入schedule从office_hours是office_hours.schedule_id = schedule.semester_id的正确方法。

select  * 
from  schedule 
      inner join semester 
       on schedule.semester_id = semester.id 
      inner join office_hours 
       on office_hours.schedule_id = schedule.semester_id 

UPDATE 1

select  * 
from  schedule 
      inner join semester 
       on schedule.semester_id = semester.id 
      inner join office_hours 
       on office_hours.schedule_id = schedule.semester_id 
      INNER JOIN faculty 
       ON faculty.id = office_hours.faculty_id 
      INNER JOIN Section 
       ON Section.faculty_ID = faculty.id AND 
        Section.Schedule_ID = Schedule.ID 
      INNER JOIN class 
       ON Class.ID = Section.Class_ID 
      INNER JOIN major_class_br 
       ON major_class_br.class_ID = Class.ID 
      INNER JOIN major_minor 
       ON major_class_br.major_minor_id = major_minor.ID 

假定所有ID或联列存在于这就是为什么使用INNER JOIN每个表。否则，请使用LEFT JOIN。

Answer 2

您必须使用id，这是两个表中：

... 
inner join office_hours on office_hours.schedule_id = schedule.id; 

Answer 3

Tryu这样的：

SELECT * 
FROM 
SCHEDULE 
INNER JOIN semester 
ON schedule.semester_id = semester.id 
INNER JOIN office_hours 
ON office_hours.schedule_id = schedule.id