Question

如何在一个查询中连接多个表这些是我的表

registration
  registrationid
  regschedid
  studentid

registrationschedule
  regschedid

session
  sessionid
  regschedid
  sessiondate

schedules
  scheduleid
  regschedid
  teacherid

faculty
  teacherid
  fname

我想加入所有这些，以便我可以获得fname和会话日期，请帮助我..

顺便说一句，我必须指定registration.studentid才能得到实际的学生

Answer 1

要连接多个表，您可以使用与连接2个表相同的技术：

SELECT *
FROM registration
JOIN registrationschedule ON registration.regschedid = regschedid
JOIN student ON registration.studentid = student.studentid
--- etc

Answer 2

 SELECT registration.*,registrationschedule.*, session.*,schedules.*,faculty.*
 FROM registration
 LEFT JOIN registrationschedule on registration.regschedid = registrationschedule.regschedid
 LEFT JOIN session on session.regschedid = registrationschedule.regschedid
 LEFT JOIN schedules on schedules.regschedid = session.regschedid
 LEFT JOIN faculty on faculty.teacherid = schedules.teacherid
 WHERE registrationid = 1;

Answer 3

SELECT * FROM registration 
JOIN registrationschedule ON registration.regschedid=regschedid 
JOIN session ON registration.regschedid=session.regschedid 
JOIN schedules ON regschedid.regschedid=regschedid
JOIN faculty ON schedules.teacherid = faculty.techerid
WHERE student.id = ?

MySQL中的多表SQL连接

3 个答案: