mancano le parentesi di chiusura in concat
funzione
SELECT equivalent FROM tb_student_record INNER JOIN tb_student ON tb_student_record.stud_id=tb_student.stud_id
WHERE tb_student_record.instructor_id = 'INST-20131296'
AND tb_student_record.criteria_id = '1'
AND tb_student_record.class_record_id = '1'
AND (CONCAT(stud_fname, ' ', stud_lname) = 'Jeffrey Oliveras' )
AND tb_student_record.term = 'Prelim'