1つのフィールドに同じ値を持つテーブルから行を選択する

あなたはそれ自体に対して学生に参加する必要があります：

SELECT s1.initials, s1.lastName
FROM Student s1, Student s2
WHERE s1.studentId <> s2.studentID /* Every student has the same tutor as himself */
AND s1.tutorId = s2.tutorid

ペアを出力する場合：

SELECT s1.initials, s1.lastName, s2.initials, s2.lastName
FROM Student s1, Student s2
WHERE s1.studentId <> s2.studentID /* Every student has the same tutor as himself */
AND s1.tutorId = s2.tutorid

家庭教師のリストを取得するには-学生：

SELECT tutorId, GROUP_CONCAT( initials, lastName SEPARATOR ', ') 
FROM `Student` 
GROUP BY tutorId
/* to only show tutors that have more than 1 student: */
/* HAVING COUNT(studentid) > 1 */