半複雜的結果在SQL查詢中設置

Question

我有一個user表像這樣

FIRSTNAME | LASTNAME | ID | 
-------------------------------- 
James  | Hay  | 1 | 
Other  | Person | 2 | 

我也有一個attendance表這樣

EVENTID | USERID | ATTENDANCE | STATUS | 
----------------------------------------------- 
1   1   True   3 
2   1   False   1 
3   1   False   3 
1   2   False   1 
2   2   True   3 
3   2   True   3 

基本上，當用戶受邀參加的活動，一行被添加到attendance表中，該表具有事件ID，他們的用戶ID，假出勤和狀態0.

狀態僅僅是第eir響應

0 = No Response 
1 = Said No 
2 = Said Yes 
3 = Said yes and seats confirmed 

我最終的結果我想從查詢這兩個表中得到很複雜，我不知道我需要做什麼。

我希望得到這樣的結果

NAME   | % of saying YES to an RSVP | % of attending after saying yes 
------------------------------------------------------------------------------- 
James Hay  |    66    |    50 
Other Person |    66    |    100 

我敢肯定，你可以工作，我是如何得到這些數字卻說明，詹姆斯干草有3（是的）狀態到2/3事件邀請。所以說是的是％66走出2，他說好，他只參加了出席的1/2那麼％的人說是後50％

在正確的軌道任何推會很多，因爲我在這裏感謝我無法理解這一點。

編輯：

同樣的東西很重要，是我想要的結果，包括數據庫中的每個用戶，即使他們在attendance表0行。

Answer 1

SELECT A.NAME,B.PERCENTAGE_YES_RSVP,B.PERCENTAGE_AFTER_YES 
FROM 
( 
    SELECT U.ID AS ID,U.FIRSTNAME+''+U.LASTNAME AS NAME 
    FROM USERS U 
) A, 
(
    SELECT A.USERID,A.PERCENTAGE_YES_RSVP,B.PERCENTAGE_AFTER_YES 
FROM 
    (
    SELECT B.USERID,ROUND((CAST(B.COUNT_YES_RSVP AS FLOAT)/B.TOTAL_COUNT)*100,0) AS PERCENTAGE_YES_RSVP  
    FROM 
    (SELECT A.USERID, 
     SUM(CASE WHEN A.STATUS=3 THEN 1 END)AS COUNT_YES_RSVP, 
     COUNT(*) AS TOTAL_COUNT 
     FROM ATTENDANCE A 
     GROUP BY A.USERID 
    ) B 
) A, 
(
    SELECT C.USERID,(CAST(C.COUNT_AFTER_YES_RSVP AS FLOAT)/C.TOTAL_COUNT)*100 AS PERCENTAGE_AFTER_YES 
    FROM 
    (SELECT A.USERID, 
     SUM(CASE WHEN A.STATUS=3 AND A.ATTENDANCE='TRUE' THEN 1 END)AS COUNT_AFTER_YES_RSVP, 
     SUM(CASE WHEN A.STATUS=3 THEN 1 END) AS TOTAL_COUNT 
    FROM ATTENDANCE A 
    GROUP BY A.USERID 
    ) C 
)B 
WHERE A.USERID=B.USERID 
) B 
WHERE A.ID = B.USERID; 

Answer 2

編輯：

哎呀，忘了加入的用戶:)

select firstname, lastname, 
    convert(decimal (5, 2), 1. * count(case when status in (2, 3) then 1 end)/count(*) * 100) SaidYes, 
    convert(decimal (5, 2), 1. * count(case when status in (2, 3) and attendance = 'True' then 1 end)/count(case when status in (2, 3) then 1 end) * 100) ActuallyAttended 
from attendance a 
join users u on a.userid = u.id 
group by firstname, lastname 

Answer 3

select 
u.firstname, u.lastname 
-- said yes, as percentage 
,floor(100.0 
    * count(case when a.status in (2,3) then 1 end) 
    /count(u.id)) yes 
-- attended after saying yes, as percentage 
,floor(100.0 
    * count(case when a.status in (2,3) and attendance='true' then 1 end) 
    /nullif(count(case when a.status in (2,3) then 1 end),0)) attendance 
--,count(u.id) rsvp -- total invites 
from users u 
left join attendance a on a.userid = u.id 
group by u.firstname, u.lastname 

注：對於該用戶從未收到邀請的特殊情況的統計數據顯示爲0％和NULL。

說明條款：

• count(case when a.status in (2,3) then 1 end)
  • 代表了多少次，他們說是的，使用了兩次
• count(u.id)
  • 多少邀請（記錄考勤）接受。特殊情況是，當他們收到沒有，在這種情況下，LEFT JOIN使得1（並不重要）多少次，他們參加的
• count(case when a.status in (2,3) and attendance='true' then 1 end)
  • 計數，在已經說是