select a. 班级,A.ZRS,B.HGRS FROM (
SELECT 班级,COUNT(姓名) [ZRS] FROM TABLE group by 班级
) A
left JOIN (
SELECT 班级,COUNT(姓名) [HGRS] FROM TABLE WHERE 分数>=60 group by 班级
) B ON A.班级=B.班级
------------
差了group by
selet 班级,count(姓名) as 总人数,sum(case when 成绩>59 then 1 else 0 end) as 合格人数
from score GROUP BY 班级;