SQL Percentage Group By

Question

我需要提供员工演示者及其客户端课堂出勤率的快速报告，并且我试图找出SQL（针对SQL Server）中的正确查询。

客户端是单独安排的课程，所以在表tSchedule中，每一行都有一个类名，课程的时间和日期，客户端名称，课堂演示者的名字以及客户端的出席状态（例如'present '，'缺席'，'缺席w /辩解'，'迟'等）

所以我需要一个SQL查询，它会为每个演示者输出一行，在给定日期范围内的演讲者的班级，实际出席的总人数（即，“出席”或“缺席/出借”的出席状态）以及这些“现在或原谅”客户总数的百分比。

下面添加在一些细节上每回复：

tSchedule 

class   class_date  Employee_id  client_id  attendance_status 
Basket Weaving 2017-07-13  231    712    Present 
Basket Weaving 2017-07-13  231    121    Present 
Basket Weaving 2017-07-13  231    186    Absent 
Basket Weaving 2017-07-13  231    666    Absent 
Juggling   2017-07-13  900    111    Present 
Juggling   2017-07-13  900    222    Present 
Juggling   2017-07-13  900    333    Present 
Juggling   2017-07-13  900    712    Absent w/Excuse 



Expected Result of Query: 

Employee_id Clients Scheduled Clients Present or Excused Attendance Rate 
231   4     2       50% 
900   4     4       100% 

（附录） 好吧，我已经结束了使用（如下图）作品的查询，但它的丑陋，我敢肯定不理想。如果有人知道获得相同结果的最优雅的方式，我非常感谢。 （@参数1和@ param2的是为所需的时间跨度的开始和结束日期用户输入的日期）

Select 
    pl.emp_id 
    ,e.last_name + ', ' + e.first_name as facilitator 
    ,count(pl.emp_id) as total_Count 
    ,(select count(*) from planner where emp_id = pl.emp_id 
     and visit_status in ('ARRIVED', 'PRESENT WITH JS', 'PRESENT NO JS') 
     and plan_date >= @param1 
     and plan_date <= @param2) as attended_Count 
    ,cast(cast((select count(*) from planner where emp_id = pl.emp_id 
     and visit_status in ('ARRIVED', 'PRESENT WITH JS','PRESENT NO JS') 
     and plan_date >= @param1 
     and plan_date <= @param2) as float)/cast((select count(*) from 
     planner where emp_id = pl.emp_id 
     and plan_date >= @param1 
     and plan_date <= @param2) as float) * 100 as decimal (18,2)) as attendance_percent 
from planner pl inner join employees e on pl.emp_id = e.emp_id 
where pl.program_id = 2 
    and pl.visittype_id in (42,173) 
    and plan_date >=@param1 
    and plan_date <= @param2 
group by pl.emp_id, e.last_name + ', ' + e.first_name 

Answer 1

select 
    status, 
    cnt*100.0/total 
from 
(select c status,count(*) cnt from attendance c group by c.status), 
(select count(*)total from attendance c)