SSMS SQL-將表中的一行與上一行進行比較-狀態更改

Question

我使用的表格包含每周機會及其各自狀態的記錄。 我想比較機會的最新狀態及其之前的一周（例如：狀態從“正在探查”變為“談判”）。 我想將與上周相比本周所有值已更改的那些插入到新表中。 注意：在該表的“周”中，0是當前周，1是前一周，2是前兩周，依此類推。

表歷史記錄示例：

+--------+---------+-------------+-----+
|Acc_Num | Opp_Num |    Stage    | Week|
+--------+---------+-------------+-----+
|   1    |    1    |     Won     |  0  |
+--------+---------+-------------+-----+
|   1    |    1    | Negotiation |  1  |
+--------+---------+-------------+-----+
|   1    |    1    | Prospecting |  2  |
+--------+---------+-------------+-----+
|   1    |    2    | Prospecting |  0  |
+--------+---------+-------------+-----+
|   1    |    2    | Prospecting |  1  |
+--------+---------+-------------+-----+
|   2    |    1    | Negotiation |  0  |
+--------+---------+-------------+-----+
|   2    |    1    | Prospecting |  1  |
+--------+---------+-------------+-----+

例如目標表：

+--------+---------+-------------+-----+
|Acc_Num | Opp_Num |    Stage    | Week|
+--------+---------+-------------+-----+
|   1    |    1    |     Won     |  0  |
+--------+---------+-------------+-----+
|   1    |    1    | Negotiation |  1  |
+--------+---------+-------------+-----+
|   2    |    1    | Negotiation |  0  |
+--------+---------+-------------+-----+
|   2    |    1    | Prospecting |  1  |
+--------+---------+-------------+-----+

我停留在比較上周各個階段的第一步。 這是我嘗試過但無法使用的SQL代碼：

SELECT *
INTO Goal_Table
FROM (
SELECT  Acc_Num
        ,Opp_Num
        ,Stage
        ,Week
        ,CONCAT(Acc_Num, Opp_Num,Week) AS Unq_ID
        FROM Table_History) as A
Left Join
(SELECT  Acc_Num
        ,Opp_Num
        ,Stage
        ,Week
        ,CONCAT(Acc_Num, Opp_Num,Week) AS Unq_ID
        FROM Table_History) as B
ON A.Unq_ID=B.Unq_ID AND A.Week=B.Week-1

我不斷收到有關列名需要唯一的錯誤。 這是實際的錯誤文本：“每個表中的列名必須是唯一的。表'Goal_Table'中的列名'Acc_Num'被多次指定。

感謝您的幫助或指導

Answer 1

使用分析功能可以更輕松地完成此操作，分析功能更易於閱讀，甚至更快。 當您引用ssms時，我將提供一個使用t-sql的示例：

create table dbo.Table_History
(
    Acc_Num int,
    Opp_Num int,
    Stage nvarchar(50),
    WeekNumber int
)
insert into dbo.Table_History
values
    (1,1,'won',0),
    (1,1,'Negotiation',1),
    (1,1,'Prospecting',2),
    (1,2,'Prospecting',0),
    (1,2,'Prospecting',1),
    (2,1,'Negotiation',0),
    (2,1,'Prospecting',1)

WITH CompareWeeks AS
(
    SELECT
        Acc_Num AS Acc_Num,
        Opp_Num AS Opp_Num,
        Stage AS Stage_Cur,
        WeekNumber as WeekNumber_cur,
        lag(Stage) over (partition by Acc_Num, Opp_Num order by WeekNumber desc) AS Stage_prev,
        lag(WeekNumber) over (partition by Acc_Num, Opp_Num order by WeekNumber desc) as WeekNumber_prev
    FROM dbo.Table_History
)
SELECT
    Acc_Num,
    Opp_Num,
    Stage_Cur,
    WeekNumber_cur
--INTO dbo.GoalTable
FROM CompareWeeks
WHERE Stage_Cur <> Stage_prev and Stage_prev is not null

請注意，您上面提供的示例似乎不一致。 您沒有考慮（1,1）的第一行，但考慮了（2,1），即使沒有一周可以比較。