写了一个你看看，举例为三种课程
SELECT count(case when cou1 >=60 then 1 else null end ) /count(*) as kecheng1,
count(case when cou2 >=60 then 1 else null end ) /count(*) as kecheng2,
count(case when cou3 >=60 then 1 else null end ) /count(*) as kecheng3
from world.gradedata001
