TSQL用于对不同的记录进行排序，然后应用行号

Question

我问了一个关于在软件激活场景中处理锁定的问题，在这个场景中，当处理新的激活时，旧的激活被锁定。

SQL Server Stored Procedure to dump oldest X records when new records added

我遇到了一个问题，希望有人能帮上忙。让我们假设Activations表包含以下列：

CustomerName、ProductName、KeyCode、ActivationDate

我需要获取唯一的CustomerName、ProductName和KeyCode数据，因为您可以多次激活同一台机器。结果集需要按ActivationDate DESC排序，以便我可以按激活的顺序处理数据。因此，在我的场景中，我可能会允许最后两个激活工作，所有这些都是在登录到Lockout表之前，这样它们就会被记录的新激活锁定。

如何对唯一/不同的结果集进行排序，然后应用行号，这样我就可以迭代结果集，丢弃最新的激活并使用较旧的激活来锁定它们？

谢谢。

Answer 1

我认为这会做你想要的：

select t.CustomerName, t.ProductName, t.KeyCode, t.MaxDate,
       row_number() over (order by t.MaxDate desc) as RowNum
    from (select CustomerName, ProductName, KeyCode, max(ActivationDate) as MaxDate
              from Activations
              group by CustomerName, ProductName, KeyCode) t

它也可以使用CTE编写，如下所示：

;with cteMaxDate as (
    select CustomerName, ProductName, KeyCode, max(ActivationDate) as MaxDate
        from Activations
        group by CustomerName, ProductName, KeyCode
)
select t.CustomerName, t.ProductName, t.KeyCode, t.MaxDate,
       row_number() over (order by t.MaxDate desc) as RowNum
    from cteMaxDate t

Answer 2

我认为这就是您要找的:您想要行号不是最大ActivationDate的所有行

DECLARE @tbl TABLE
(
    CustomerName    VARCHAR(20),
    ProductName     VARCHAR(20),
    KeyCode         INT,
    ActivationDate  DATETIME
)


INSERT INTO @tbl
SELECT 'cmp1', 'game', 28734, GETDATE() -1    UNION ALL
SELECT 'cmp1', 'game', 28734, GETDATE() -1.5  UNION ALL
SELECT 'cmp1', 'game', 28734, GETDATE() -1.2  UNION ALL
SELECT 'cmp1', 'game', 28734, GETDATE() -1.8  UNION ALL
SELECT 'cmp1', 'game', 28734, GETDATE()       UNION ALL
SELECT 'cmp1', 'game', 28734, GETDATE() -17   UNION ALL
SELECT 'cmp2', 'game', 28736, GETDATE() -1    UNION ALL
SELECT 'cmp2', 'game', 28736, GETDATE() -1.5  UNION ALL
SELECT 'cmp2', 'game', 28736, GETDATE() -1.2  UNION ALL
SELECT 'cmp2', 'game', 28736, GETDATE() -1.8  UNION ALL
SELECT 'cmp2', 'game', 28736, GETDATE()       UNION ALL
SELECT 'cmp2', 'game', 28736, GETDATE() -17     


SELECT        ROW_NUMBER() OVER(ORDER BY ActivationDate DESC) RowNumber,
              CustomerName, 
              ProductName, 
              KeyCode, 
              ActivationDate        
FROM @tbl workTable
WHERE ActivationDate != 
    (
        SELECT MAX(ActivationDate)
        FROM @tbl checkTable
        WHERE workTable.CustomerName = checkTable.CustomerName
            AND workTable.ProductName = checkTable.ProductName
            AND workTable.KeyCode = checkTable.KeyCode
    )

RowNumber     CustomerName     ProductName     KeyCode  ActivationDate
1             cmp1             game            28734    2011-02-24 08:40:45.790
2             cmp2             game            28736    2011-02-24 08:40:45.790
3             cmp2             game            28736    2011-02-24 03:52:45.793
4             cmp1             game            28734    2011-02-24 03:52:45.793
5             cmp1             game            28734    2011-02-23 20:40:45.790
6             cmp2             game            28736    2011-02-23 20:40:45.790
7             cmp2             game            28736    2011-02-23 13:28:45.790
8             cmp1             game            28734    2011-02-23 13:28:45.790
9             cmp1             game            28734    2011-02-08 08:40:45.790
10            cmp2             game            28736    2011-02-08 08:40:45.790

如果你想要更多...

SELECT  ROW_NUMBER() OVER(ORDER BY ActivationDate DESC) RowNumber,
        CustomerName, 
        ProductName, 
        KeyCode, 
        ActivationDate      
FROM @tbl workTable
WHERE NOT ActivationDate IN 
    (
        SELECT TOP 2 ActivationDate
        FROM @tbl checkTable
        WHERE workTable.CustomerName = checkTable.CustomerName
            AND workTable.ProductName = checkTable.ProductName
            AND workTable.KeyCode = checkTable.KeyCode
        ORDER BY ActivationDate DESC
    )