谢谢你的回答。但我认为加入并不是解决这个问题的好方法。我已经通过两个查询完成了（也许不是个好主意，但比join更好）：

SET @studyFieldID =(SELECT `studyFieldID` FROM `b_PersonEmployment` WHERE `personID`=1 ORDER BY `startDate` limit 1); 
SELECT * FROM `C_Institute`
 WHERE `ID` IN
 (SELECT `instituteID` FROM `C_Faculty` WHERE `ID` 
 IN (SELECT `facultyID` FROM `C_EducationalGroup` WHERE `ID` 
 IN (SELECT `educationalGroupID` FROM `C_StudyField` WHERE `ID`=@studyFieldID 
  )));

假设每个表中的id引用另一个表，
试试这个，告诉我：

select * from C_Institute c join C_Faculty f on c.ID=F.instituteID left join C_EducationalGroup e on f.ID=e.facultyID left join C_StudyField sf on e.ID=sf.educationalGroupID left join b_PersonEmployment p on sf.ID=p.studyFieldID where p.personID=1 order by p.startDate limit 1;

另外，分享你的表格描述以获得更多线索

您可以将此查询重写为一系列联接：

SELECT c1.*
FROM C_Institute c1
INNER JOIN C_Faculty c2
    ON c1.ID = c2.instituteID
INNER JOIN C_EducationalGroup c3
    ON c2.ID = c3.facultyID
INNER JOIN C_StudyField c4
    ON c3.ID = c4.educationalGroupID
INNER JOIN b_PersonEmployment b
    ON c4.ID = b.studyFieldID
WHERE b.personID = 1
ORDER BY b.startDate
LIMIT 1;