mysql-同一表上的三个连接

试试这个:

select sp.fullname studentname, fp.fullname fathername, mp.fullname mothername
  from students s
 inner join persons sp on (s.student_id = sp.person_id)
 inner join persons fp on (s.father_id = fp.person_id)
 inner join persons mp on (s.mother_id = mp.person_id)

尝试下面的查询-

SELECT p.fullname,m.fullname,f.fullname from students s
    LEFT JOIN persons p ON s.person_id = p.id
    LEFT JOIN mother m ON s.mother_id = m.id
    LEFT JOIN father f ON s.father_id = f.id
    WHERE s.student_id = 'id of which student record you want';