student subjects in a block query snippets

SELECT DISTINCT sai.stud_applicant_id,sai.ppd_firstname,cbas.block_name FROM college_block_active_semester cbas
inner join college_block_subject_schedule cbss ON cbss.ccb_id = cbas.cbas_id
inner join college_subject_schedule css ON css.college_subject_schedule_id = cbss.css_id
inner join college_enrolled_subjects_2016_2017 ces ON ces.css_id = css.college_subject_schedule_id
inner join student_applicant_information sai ON sai.stud_applicant_id = ces.sai_id
WHERE ces.yl_id = 19 AND cbas.cbas_id =1