select course_id,course_name,round(cnt1/cnt2*100,2) as attend_rate from ( select course_id, course_name, count(distinct if(timestampdiff(second,in_datetime,out_datetime)/60>=10,t2.user_id,null)) as cnt1, count(distinct t1.user_id) as cnt2 from course_tb left join behavior_tb as t1 using(course_id...