的Oracle SQL - 使用日期功能，提高查詢

Question

我有這個疑問

--Retention by DOC,Users created >= Jan 1,2012-- 
Select 
One.Date_Of_Concern, 
Two.Users, 
One.Retained, 
Round(One.Retained/Two.Users,4) as Perc_Retained 
From 
(
Select 
To_Date('2012-sep-09','yyyy-mon-dd')As Date_Of_Concern, 
Count(P.Player_Id) As Retained 
From Player P 
Where 
Trunc(P.Create_Dtime) >= To_Date('2012-Jan-01','yyyy-mon-dd') 
And 
(To_Date('2012-sep-09','yyyy-mon-dd')-Trunc(P.Init_Dtime))<=7 
) One 
Inner Join 
(
Select 
To_Date('2012-sep-09','yyyy-mon-dd')As Date_Of_Concern, 
Count(P.Player_Id) As Users 
From Player P 
Where 
Trunc(P.Create_Dtime) >= To_Date('2012-Jan-01','yyyy-mon-dd') 
) Two On One.Date_Of_Concern = Two.Date_Of_Concern 

這給了我1行的結果：

Date_Of_Concern  USERS  RETAINED  PERC_RETAINED 
09-Sep-12   449773 78983  0.1756 

我想通過改善查詢增加了某種日期變化方法。這樣，我不必每次都運行查詢09-sep-12，10-sep-12，11-sep-12等等。相反，它都將在同一個查詢顯示出來，就像這樣：

Date_Of_Concern  USERS  RETAINED  PERC_RETAINED 
09-Sep-12   449773 48783  0.1756 
10-Sep-12   449773 46777  0.1600 
11-Sep-12   440773 44852  0.1500 
12-Sep-12   349773 42584   0.1400 

Answer 1

那麼，與給定的信息，我不知道你是否有你可以加入，並把這些日期的任何表。但是，如果你不這樣做，你可以試試這個：

我們必須產生行並以順序形式重現日期。但首先，讓我們給看看如何生成行：

生成5行：

SELECT rownum 
FROM dual 
CONNECT BY LEVEL <= 5; 

ROWNUM 
---------- 
     1 
     2 
     3 
     4 
     5 

現在，應用此重現您所選日期數據來源：

SELECT to_date('2012-sep-09','yyyy-mon-dd') + (rownum -1) as Date_Of_Concern 
FROM dual 
CONNECT BY LEVEL <= 5; 

Date_Of_Concern 
---------- 
2012-sep-09 
2012-sep-10 
2012-sep-11 
2012-sep-12 
2012-sep-13 

顯然你將需要一個開始日期。此外，5號，要由你需要的日期數來代替，這可能是一個日期範圍像

SELECT to_date('2012-sep-09','yyyy-mon-dd') + (rownum -1) date 
FROM dual 
CONNECT BY LEVEL <= (to_date('2012-sep-20','yyyy-mon-dd') - to_date('2012-sep-09','yyyy-mon-dd')); 

OK，現在最後的結果是這樣的：

SELECT both.Date_Of_Concern, 
     both.Retained, 
     both.Users, 
     Round(both.Retained/both.Users,4) as Perc_Retained 
    FROM (select Date_Of_Concern, 
       (Select Count(P.Player_Id) As Retained 
       From Player P 
       Where Trunc(P.Create_Dtime) >= To_Date('2012-Jan-01','yyyy-mon-dd') 
        And (Date_Of_Concern-Trunc(P.Init_Dtime))<=7) Retained, 
       (Select Count(P.Player_Id) As Users 
        From Player P 
        Where Trunc(P.Create_Dtime) >= To_Date('2012-Jan-01','yyyy-mon-dd') 
       ) Users 
      from (SELECT to_date('2012-sep-09','yyyy-mon-dd') + (rownum -1) Date_Of_Concern, 
       FROM dual 
       CONNECT BY LEVEL <= 5)) both 

Answer 2

我有一種感覺，你的查詢可以簡化很多。這裏試圖從2012年初開始逐日列出。取決於你想要的範圍。

SELECT date_of_concern 
     ,Running_Total_Users AS Users 
     ,Running_Total_Retained As Retained 
     ,ROUND(Running_Total_Retained/Running_Total_Users, 4) AS Perc_Retained 

    FROM (SELECT date_of_concern 

       ,SUM(Users) OVER(ORDER BY date_of_concern 
           ROWS BETWEEN UNBOUNDED PRECEDING 
              AND CURRENT ROW) AS Running_Total_Users 

       ,SUM(Retained) OVER(ORDER BY date_of_concern 
           ROWS BETWEEN UNBOUNDED PRECEDING 
              AND CURRENT ROW) AS Running_Total_Retained 

      FROM (SELECT TRUNC(Create_Dtime) date_of_concern 
         ,COUNT(Player_Id) Users 
         ,SUM(CASE WHEN (TRUNC(Create_Dtime) - TRUNC(Init_Dtime)) <= 7 THEN 1 ELSE 0 END) AS Retained 
        FROM player ON (TRUNC(.Create_Dtime) >= TO_DATE('2012', 'YYYY')) 
       ) 
     ) 

最內層查詢是嘗試重新編寫從第1天開始計數的發佈查詢（2012年1月1日）。然後下一個包裝應該爲隨後的每一天執行總計。最後的包裝是啓用Perc_Retained。當然完成未經測試:)