Query : SELECT c.*,
(select count(*) from subject where course_id = c.course_id) as subject_count ,
(select count(*) from subject s inner join qi_lecture l on s.subject_id = l.education_no and l.lec_type = 'PRO' where s.course_id = c.course_id) as lecture_count,
(select sum(duration) from qi_lecture ql inner join subject s on s.subject_id = ql.education_no where s.course_id = c.course_id and lec_type = 'PRO') as lecture_duration_sum
FROM course c WHERE c.course_status in ('READY', 'OK') Order By c.course_order, c.course_id
