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Question

我有一個表像這樣

DateTime start_time not null, 
DateTime end_time not null, 
Status_Id int not null, 
Entry_Id int not null 

我希望得到一個時間段，其中只有最後開始的有效期爲一個給定的entry_id內各狀態下的計數。

我現在使用的就是這個（動態日期）：

with c (Status_Id, Entry_Id, Start_Date) AS (
    select Status_Id, Entry_Id, Start_Date from tbl where 
    (End_Date BETWEEN '19000101' AND '21000101') 
    AND ((Start_Date BETWEEN '19000101' AND '21000101') 
    OR End_Date <= '21000101')) 
select Status_Id, count(*) as cnt from 
(select Entry_Id, max(start_date) as start_date from c 
    group by Entry_Id) d inner join 
c on c.Entry_Id = d.Entry_Id 
and c.start_date = d.start_date 
GROUP BY Status_Id WITH ROLLUP 

的問題是，它的時候有一些entry_id具有多個條目的相同的起始日期計算錯誤。 （我並不特別在意選擇在這種情況下，其地位，就只有1選擇）

一些測試數據：

status_id Entry_id Start_date 
496 45173 2010-09-29 18:04:33.000 
490 45173 2010-09-29 18:48:20.100 
495 45173 2010-09-29 19:25:29.300 
489 45174 2010-09-29 18:43:01.500 
493 45175 2010-09-29 18:48:00.500 
493 45175 2010-09-29 21:16:02.700 
489 45175 2010-09-30 17:52:12.100 
493 45176 2010-09-29 17:55:21.300 
492 45176 2010-09-29 18:20:52.200 <------ This is the one that gives the problems 
493 45176 2010-09-29 18:20:52.200 <------ This is the one that gives the problems 

結果應該是

495 1 
489 2 
492 1 (or 493 1) 

Answer 1

阿爾特原生答案基於OP的可愛評論。只需要

WITH 
    [sequenced_data] 
AS 
(
    SELECT 
    *, 
    ROW_NUMBER() OVER (PARTITION BY entry_id ORDER BY start_time DESC, status_id DESC) AS [sequence_id] 
    FROM 
    tbl 
    WHERE 
    start_time < '21:00' AND end_time > '19:00' 
) 
SELECT status_id, COUNT(*) 
FROM [sequenced_data] 
WHERE sequence_id = 1 
GROUP BY status_id 

的ROW_NUMBER（）函數，其中沒有單個字段可以唯一識別individul記錄。在數據中存在唯一標識列的情況下，可以編寫其他查詢。但是，SQL Server在優化如上所述的ROW_NUMBER（）查詢方面非常有效，它應該（假設相關索引）有效。

編輯

剛纔有人向我建議人們不喜歡長的代碼，他們更喜歡緊湊的代碼。所以CTE版本已替換爲內嵌版本（CTE的真的只是幫擊穿解釋原因的查詢，並在必要時編輯歷史）...

編輯

ROW_NUMBER（）無法形成OP所發現的WHERE子句的一部分。通過重新放置一個CTE來更新查詢。

Answer 2

如果我正確理解，您想在您的時間段內爲特定狀態計入不同的條目......如果是這樣，則應使用count()中的DISTINCT子句從計數（*）變爲計數（不同的Entry_id）

with c (Status_Id, Entry_Id, Start_Date) AS (
    select Status_Id, Entry_Id, Start_Date from tbl where 
    (End_Date BETWEEN '19000101' AND '21000101') 
    AND ((Start_Date BETWEEN '19000101' AND '21000101') 
    OR End_Date <= '21000101')) 
select Status_Id, count(distinct Entry_Id) as cnt from 
(select Entry_Id, max(start_date) as start_date from c 
    group by Entry_Id) d inner join 
c on c.Entry_Id = d.Entry_Id 
and c.start_date = d.start_date 
GROUP BY Status_Id WITH ROLLUP 

編輯

只要你不關心哪個狀態是返回給定項，我想你可以修改內部查詢返回的第一地位和加入的狀態太

with c (Status_Id, Entry_Id, Start_Date) AS (
    select Status_Id, Entry_Id, Start_Date from tbl where 
    (End_Date BETWEEN '19000101' AND '21000101') 
    AND ((Start_Date BETWEEN '19000101' AND '21000101') 
    OR End_Date <= '21000101')) 
select c.Status_Id, count(c.Entry_Id) as cnt from 
(select Entry_Id, Start_Date, (select top 1 Status_id from c where Entry_Id = CC.Entry_Id and Start_Date = CC.Start_Date) as Status_Id 
    from (select Entry_Id, max(start_date) as start_date from c 
    group by Entry_Id) as CC) d inner join 
c on c.Entry_Id = d.Entry_Id 
and c.start_date = d.start_date 
and c.status_id = d.status_id 
GROUP BY c.Status_Id 

結果

Status_id Count 
489  2 
492  1 
495  1 

Answer 3

我找到了解決自己：

with c (Status_Id, Entry_Id, Start_Date) AS (
    select Status_Id, Entry_Id, Start_Date from tbl where 
    (End_Date BETWEEN '19000101' AND '21000101') 
    AND ((Start_Date BETWEEN '19000101' AND '21000101') 
    OR End_Date <= '21000101')) 
select Status_Id, count(*) as cnt from 
(select max(Status_Id) as Status_Id, c.Entry_Id from --<--- ADDED 
(select Entry_Id, max(start_date) as start_date from c 
    group by Entry_Id) d inner join 
c on c.Entry_Id = d.Entry_Id 
and c.start_date = d.start_date 
group by c.Entry_Id) y --<--- ADDED 
GROUP BY Status_Id WITH ROLLUP