SQL查詢查找以前的記錄

Question

我很努力地寫一個基於下面的表的查詢應該得到一個位置（其中BadRec = 1）的Bad記錄以及該位置上的前3個記錄（Max），包括壞記錄;

TranDate    Location BadRec 
======================= ======== ====== 
2010-08-25 00:00:00.000 STN-2  0 
2010-08-26 00:00:00.000 STN-2  1 
2010-08-27 00:00:00.000 STN-1  1 
2010-08-28 00:00:00.000 STN-1  0 
2010-08-28 00:00:00.000 STN-2  1 
2010-08-29 00:00:00.000 STN-1  0 
2010-08-30 00:00:00.000 STN-1  1 
2010-08-31 00:00:00.000 STN-1  0 
2010-09-01 00:00:00.000 STN-1  0 

這裏是預期的推出;

TranDate    Location BadRec comments 
======================= ======== ====== ======== 
2010-08-30 00:00:00.000 STN-1  1 <- Bad record on STN-1 
2010-08-29 00:00:00.000 STN-1  0 <- First Previous record 
2010-08-28 00:00:00.000 STN-1  0 <- Second Previous record 
2010-08-27 00:00:00.000 STN-1  1 <- Third Previous record (Previous include bad rec) 
2010-08-28 00:00:00.000 STN-2  1 <- Bad record on STN-2 
2010-08-26 00:00:00.000 STN-2  1  
2010-08-25 00:00:00.000 STN-2  0  
2010-08-27 00:00:00.000 STN-1  1 <- Bad record on STN-1,No previous record for this 
2010-08-26 00:00:00.000 STN-2  1 <- Bad record on STN-2 
2010-08-25 00:00:00.000 STN-2  0  

這是可能寫這個使用單個查詢？使用CTE？結束（分區...）??任何幫助，非常感謝。 注意：我在SQL 2005機器上;

Answer 1

這是做你想做的嗎？

SELECT TranDate, Location, BadRec 
FROM 
    (
    SELECT pr.TranDate, pr.Location, pr.BadRec, 
     ROW_NUMBER() OVER (PARTITION BY r.TranDate ORDER BY pr.TranDate DESC) AS SEQUENCE 
    FROM Records r 
    JOIN Records pr ON r.Location = pr.Location 
        AND r.TranDate >= pr.TranDate 
    WHERE r.BadRec = 1 
    ) x 
WHERE SEQUENCE <= 4