t.teacher_id_ as "teacherId" , t.student_id_ as "studentId" , t.create_time_ as "createTime" select t.teacher_id_ as userId, count(1) as fansNum from student_star t group by t.teacher_id_ select t.student_id_ as userId, count(1) as starTeacherNum from student_star t group by t.student_id_ select from student_star t where t.student_id_ = #{studentId} and t.teacher_id_ = #{teacherId} select * from student_star ss where ss.student_id_ = #{studentId} delete from student_star where student_id_ = #{studentId} and teacher_id_ = #{teacherId}