复杂SQL案例：用户退款信息查询

供参考：

select 
t3.course_id 课程id,
t3.user_id 用户ID,
u.user_full_name 姓名,
-- u.phone,
concat(u.company,' ',ex.user_enterprise) 公司或企业,
t3.right_1 权限状态,
t3.right_0 退款数,
t3.exit_date 退款日期
from 
(
select 
course_id,
user_id,
sum(right_1) right_1,
sum(right_0) right_0,
group_concat(exit_date) exit_date
from
(
		select
		course_id,user_id,
		(case current_status when 1 then 1 else 0 end ) right_1,
		(case current_status when 0 then 1 else 0 end ) right_0,
        (case current_status when 0 then update_date else null end ) exit_date
		from 
		(
			select distinct course_id,user_id,date(create_time) create_date,current_status,
             date_format(update_time,'%Y-%m-%d %H:%i') update_date
			from app_goods.user_rights_course
			where course_id=${corse_id}
		) t1
) t2
where 1=1
group by course_id,user_id
having sum(right_0)>=2 
) t3 left join app_user.user_info u on t3.user_id=u.id
     left join app_user.user_extend_info ex on t3.user_id=ex.user_id 
order by t3.course_id,t3.right_0 desc