sql-server - SQL Server 2005 T-SQL 问题 : Need help in omitting records

Question

再会!

我在编写查询时需要帮助.. 我在下表中有记录.. 如果后续记录的 new_state 与之前的记录 (new_state) 重复，并且如果它在相同的记录中更改，则不应显示任何记录日期..

这里record_id 1已经经历了ff状态:0->1->2->1->3->4->3在同一天..状态1被更改为状态2然后再次回到状态1(id 2 & 3 不会显示.. 与状态 3 相同(id 5 & 6 不会显示)..

id | record_id| date_changed | old_state | new_state |
1  | 1        | 2009-01-01   | 0         | 1         |
2  | 1        | 2009-01-01   | 1         | 2         | not displayed
3  | 1        | 2009-01-01   | 2         | 1         | not displayed
4  | 1        | 2009-01-01   | 1         | 3         |
5  | 1        | 2009-01-01   | 3         | 4         | not displayed
6  | 1        | 2009-01-01   | 4         | 3         | not displayed

所以结果将只显示 record_id=1 的 2 条记录..

id | record_id| date_changed | old_state | new_state |
1  | 1        | 2009-01-01   | 0         | 1         |
4  | 1        | 2009-01-01   | 1         | 3         |

这是表创建和数据的代码:

IF OBJECT_ID('TempDB..#table','U') IS NOT NULL
      DROP TABLE #table
CREATE TABLE #table
(
id INT identity primary key,
record_id INT,
date_changed DATETIME,
old_state INT,
new_state INT
)
INSERT INTO #table(record_id,date_changed,old_state,new_state)
    SELECT 1,'2009-01-01',0,1 UNION ALL --displayed
    SELECT 1,'2009-01-01',1,2 UNION ALL --not displayed
    SELECT 1,'2009-01-01',2,1 UNION ALL --not displayed
    SELECT 1,'2009-01-01',1,3 UNION ALL --displayed
    SELECT 1,'2009-01-01',3,4 UNION ALL --not displayed
    SELECT 1,'2009-01-01',4,3           --not displayed

INSERT INTO #table(record_id,date_changed,old_state,new_state)
    SELECT 3,'2009-01-01',0,1 UNION ALL --displayed
    SELECT 3,'2009-01-01',1,2 UNION ALL --not displayed
    SELECT 3,'2009-01-01',2,3 UNION ALL --not displayed
    SELECT 3,'2009-01-01',3,4 UNION ALL --not displayed
    SELECT 3,'2009-01-01',4,1           --not displayed

SELECT * FROM #table

我将不胜感激任何帮助..

谢谢

为清楚起见，record_id=3 .. 鉴于此表:

id | record_id| date_changed | old_state | new_state |
7  | 3        | 2009-01-01   | 0         | 1         |
8  | 3        | 2009-01-01   | 1         | 2         | not displayed
9  | 3        | 2009-01-01   | 2         | 3         | not displayed
10 | 3        | 2009-01-01   | 3         | 4         | not displayed
11 | 3        | 2009-01-01   | 4         | 1         | not displayed

当运行 record_id=3 的查询时，表结果将是:

id | record_id| date_changed | old_state | new_state |
7  | 3        | 2009-01-01   | 0         | 1         |

谢谢!

更新(12/2/2009):

特殊场景

id | record_id| date_changed | old_state | new_state |
1  | 4        | 2009-01-01   | 0         | 1         | displayed
2  | 4        | 2009-01-01   | 1         | 2         | displayed
3  | 4        | 2009-01-01   | 2         | 3         | not displayed
4  | 4        | 2009-01-01   | 3         | 2         | not displayed
5  | 4        | 2009-01-01   | 2         | 3         | displayed
6  | 4        | 2009-01-01   | 3         | 4         | not displayed
7  | 4        | 2009-01-01   | 4         | 3         | not displayed

其中 new_state 3 出现在 id 3,5 和 7.. id 3 不会被显示，因为它在具有相同 new_state(3) 的 id 2 和 id 4 之间。然后应该显示 id 5，因为没有现有的 new_state 3还..

代码片段:

IF OBJECT_ID('TempDB..#tablex','U') IS NOT NULL
      DROP TABLE #tablex

CREATE TABLE #tablex
(
id INT identity primary key,
record_id INT,
date_changed DATETIME,
old_state INT,
new_state INT
)
INSERT INTO #tablex(record_id,date_changed,old_state,new_state)
    SELECT 4,'2009-01-01',0,1 UNION ALL --displayed
    SELECT 4,'2009-01-01',1,2 UNION ALL --displayed
    SELECT 4,'2009-01-01',2,3 UNION ALL --not displayed
    SELECT 4,'2009-01-01',3,2 UNION ALL --not displayed
    SELECT 4,'2009-01-01',2,3 UNION ALL --displayed
    SELECT 4,'2009-01-01',3,4 UNION ALL --not displayed
    SELECT 4,'2009-01-01',4,3           --not displayed

我认为构建结果的顺序很重要..

谢谢!

Answer 1

SELECT A.*
/*
A.ID, A.old_state, a.new_state, 
B.ID as [Next], b.old_state, b.new_state,
C.ID as [Prev],  c.old_state, c.new_state
*/
FROM #table A LEFT JOIN 
#table B ON A.ID = (B.ID - 1)
LEFT JOIN #table C ON (A.ID - 1) = C.ID
-- WHERE A.old_State <> B.new_State AND A.new_State <> C.old_State
WHERE A.record_id = 1
AND A.old_State <> COALESCE(B.new_State, -1) 
AND A.new_State <> COALESCE(C.old_State, -1)

编辑:我想，OP 需要的是除了当前记录的旧状态与下一个记录的新状态不同(记录中的一种撤消操作)和当前记录的新状态不相同的记录之外，应该选择剩余的记录作为以前记录的旧状态。