Sql 使用CTE获取每组的最后一行
我有这样一个问题:Sql 使用CTE获取每组的最后一行,sql,sql-server,tsql,common-table-expression,Sql,Sql Server,Tsql,Common Table Expression,我有这样一个问题: DECLARE @DeadDesigns AS TABLE( LegacyKey INT ,DesignKey INT ,StatusKey INT ,DesignGroupId UNIQUEIDENTIFIER ) INSERT INTO @DeadDesigns SELECT [P].[LegacyKey],[D].DesignKey, [D].[StatusKey], [D].[DesignGroupId] FROM Project AS P INNER JOIN D
DECLARE @DeadDesigns AS TABLE(
LegacyKey INT
,DesignKey INT
,StatusKey INT
,DesignGroupId UNIQUEIDENTIFIER
)
INSERT INTO @DeadDesigns
SELECT [P].[LegacyKey],[D].DesignKey, [D].[StatusKey], [D].[DesignGroupId] FROM Project AS P
INNER JOIN DesignGroup AS DG ON P.ProjectKey = DG.ProjectKey
INNER JOIN Design AS D ON DG.DesignGroupId = D.DesignGroupId
WHERE [D].[StatusKey] = 67 --DEAD
;WITH CTE2 (LegacyKey, DesignKey, StatusKey, DesignGroupId, RN) AS (
SELECT LegacyKey, DesignKey, StatusKey, DesignGroupId,
ROW_NUMBER() OVER (PARTITION BY [LegacyKey], [DesignGroupId] ORDER BY [DesignGroupId]) AS RN
FROM @DeadDesigns
GROUP BY [DesignGroupId],[LegacyKey],DesignKey,StatusKey
)
SELECT * FROM CTE2
结构是:
一个LegacyKey
可以有多个DesignGroupId
,一个DesignGroupId
可以有多个DesignKey
目标是从项目中分离出每个DesignGroupId
的最后一个DesignKey
错误结果:
+-----------+-----------+-----------+--------------------------------------+----+
| LegacyKey | DesignKey | StatusKEy | DesignGroupId | RN |
+-----------+-----------+-----------+--------------------------------------+----+
| 14002 | 2416 | 67 | 1A07C80E-E5E2-45F0-A5D2-419BAF3DC106 | 1 |
| 14002 | 2819 | 70 | 1A07C80E-E5E2-45F0-A5D2-419BAF3DC106 | 2 |
+-----------+-----------+-----------+--------------------------------------+----+
这是错误的,因为它是相同的DesignGroupId,如果该DesignGroupId不同,则结果是正确的
详细期望结果:
我想通过DesignGroupId
将其分开,因此如果有两个不同的DesignGroupId
,则第二行的RN
应该是2。。如果我们有3个DesignGroupId
,但第二行的相同LegacyKey
RN
应该是3,依此类推。最后,我想在每个DesignGroupId
中获取所有最后的DesignKey
的LegacyKey
我做错了什么
另一个例子
+-----------+-----------+-----------+--------------------------------------+----+
| LegacyKey | DesignKey | StatusKEy | DesignGroupId | RN |
+-----------+-----------+-----------+--------------------------------------+----+
| 18288 | 3974 | 63 | F18320D8-C7A8-4A2A-AFDE-38A483C24E81 | 1 |
| 18288 | 4096 | 107 | F18320D8-C7A8-4A2A-AFDE-38A483C24E81 | 2 |
| 18288 | 7224 | 66 | F18320D8-C7A8-4A2A-AFDE-38A483C24E81 | 3 |
| 18288 | 4842 | 66 | A18320D8-C7A8-4A2A-AFDE-38A483C24E81 | 1 |
| 18289 | 7325 | 66 | 90C224D9-2514-4294-8DEC-D3EE16EC2D00 | 1 |
| 18289 | 3975 | 63 | 90C224D9-2514-4294-8DEC-D3EE16EC2D00 | 2 |
+-----------+-----------+-----------+--------------------------------------+----+
在本例中,我有两个不同的LegacyKey
,但结果是错误的,因为它返回相同DesignGroupId
的所有RN
,我只想要最后一个。期望的结果是:
+-----------+-----------+-----------+--------------------------------------+----+
| LegacyKey | DesignKey | StatusKEy | DesignGroupId | RN |
+-----------+-----------+-----------+--------------------------------------+----+
| 18288 | 7224 | 66 | F18320D8-C7A8-4A2A-AFDE-38A483C24E81 | 3 |
| 18288 | 4842 | 66 | A18320D8-C7A8-4A2A-AFDE-38A483C24E81 | 1 |
| 18289 | 3975 | 63 | 90C224D9-2514-4294-8DEC-D3EE16EC2D00 | 2 |
+-----------+-----------+-----------+--------------------------------------+----+
正如您所看到的,我得到了
DesignGroupId
的最后一个RN
,但是它们在同一个LegacyKey
中,我不希望子查询中出现groupby
。我希望在外部查询中进行过滤:
WITH CTE2 (LegacyKey, DesignKey, StatusKey, DesignGroupId, RN) AS (
SELECT LegacyKey, DesignKey, StatusKey, DesignGroupId,
ROW_NUMBER() OVER (PARTITION BY [LegacyKey], [DesignGroupId] ORDER BY [DesignGroupId] DESC) AS seqnum
FROM @DeadDesigns
)
SELECT *
FROM CTE2
WHERE seqnum = 1;
请注意,我将ORDER BY
更改为DESC
——这是您想要“最后一次”或“最近一次”某物时的典型情况