Question

我有一个项目列表，我需要重新排序，没有间隙。它始于：

ID   Sequence
123    1
125    2
155    3
158    4
165    6
170    9

我最终需要（注意序列6更改为5，序列9更改为6）

ID   Sequence
123    1
125    2
155    3
158    4
165    5
170    6

我已尝试使用此更新声明

UPDATE  tblA
SET     tblA.Sequence = temp.Sequence
FROM    ( SELECT    id ,
                    ROW_NUMBER() OVER ( ORDER BY Sequence, ID ) AS Sequence
          FROM      dbo.tblA
        ) AS temp

但我最终还是......

ID   Sequence
123    1
125    1
155    1
158    6
165    6
170    6

将select语句拉出更新会产生正确的结果。将其更改为

 UPDATE tblA
 SET    tblA.Sequence = temp.NewSequence
 FROM   ( SELECT    id ,
                    ROW_NUMBER() OVER ( PARTITION BY id ORDER BY Sequence, id ) 
                                                               AS NewSequence
          FROM      dbo.tblA
        ) AS temp

生成结果

ID   Sequence
123    1
125    1
155    1
158    1
165    1
170    1

我做错了什么？

Answer 1

您需要将重新编号的集合与原始集合中的ID相关联，否则您将使用序列号更新原始ID，以获取临时集合中的其他ID：

UPDATE a
SET a.Sequence = temp.Sequence
FROM    
    tblA a JOIN
    (
        SELECT id, ROW_NUMBER() OVER (ORDER BY Sequence, ID) AS Sequence
        FROM dbo.tblA
    ) AS temp ON temp.ID = a.ID

SQL重新排序记录

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