Question

我想就我的问题发表意见。我正在开发一个存储谷歌学者出版物的项目。因此，当我存储数据时，它就会显示出来。

ID| COLUMN1                          | COLUMN2
1 | 'Knowledge and Data Engineering' | 'IEEE transactions on 16 (1)'
1 | 'Knowledge and Data Engineering' | 'IEEE transactions on 16 (1) 28-40 '
2 | 'Data Engineering'               | '1999. Proceedings.'
2 | 'Data Engineering'               | '1999. Proceedings. 15th International Conference on '
2 | 'Data Engineering'               | '1999. Proceedings. 15th International Conference on 146-153'
3 | 'ACM SIGMOD Record 30 (2)'       | '187-198'

我希望你理解我的桌子般的绘画。我想要做的是在连续的行上有相同的ID，具有最后的行。

ID| COLUMN1                          | COLUMN2
1 | 'Knowledge and Data Engineering' | 'IEEE transactions on 16 (1) 28-40 '
2 | 'Data Engineering'               | '1999. Proceedings. 15th International Conference on 146-153'
3 | 'ACM SIGMOD Record 30 (2)'       | '187-198'

感谢您的帮助。

Answer 1

WITH CTE AS( 
SELECT Id,
       Column1,
       Column2, 
       ROW_NUMBER() OVER (PARTITION BY Column1 ORDER BY Id DESC) AS rownum
       )
SELECT Id, Column1, column2
FROM CTE 
WHERE rownum = 1

Answer 2

您可以使用 ROW_NUMBER() 窗口函数生成每ID的序号，您可以从中获取最后/最高行号。

ROW_NUMBER（）：返回结果集分区中行的序号，从1开始，每个分区的第一行。

所以我将问题分解为两个步骤：

创建包含行号的#temp表
从具有每组最高行数的临时表中选择行

SQL Fiddle Demo

MS SQL Server 2012架构设置：

CREATE TABLE Publications
    ([ID] int, [COLUMN1] varchar(34), [COLUMN2] varchar(63))
;

INSERT INTO Publications
    ([ID], [COLUMN1], [COLUMN2])
VALUES
    (1, '''Knowledge and Data Engineering''', '''IEEE transactions on 16 (1)'''),
    (1, '''Knowledge and Data Engineering''', '''IEEE transactions on 16 (1) 28-40 '''),
    (2, '''Data Engineering''', '''1999. Proceedings.'''),
    (2, '''Data Engineering''', '''1999. Proceedings. 15th International Conference on '''),
    (2, '''Data Engineering''', '''1999. Proceedings. 15th International Conference on 146-153'''),
    (3, '''ACM SIGMOD Record 30 (2)''', '''187-198''')
;

查询1 ：

-- INSERT VALUES INTO TEMP TABLE WITH ROW_NUMBER
SELECT  ID ,
        Column1 ,
        Column2 ,
        ROW_NUMBER() OVER ( PARTITION BY ID ORDER BY ID ) RowNo
INTO #TEMP
FROM    Publications

-- SELECT ROW FOR EACH ID WITH MAX ROW_NUMBER
SELECT  T1.ID, T1.Column1, T1.Column2
FROM    #TEMP T1
WHERE RowNo = (SELECT MAX(RowNo) FROM #TEMP T2 WHERE T1.ID = T2.ID)
ORDER BY ID

<强> Results ：

| ID | COLUMN1                          | COLUMN2                                                       |
|----|----------------------------------|---------------------------------------------------------------|
|  1 | 'Knowledge and Data Engineering' | 'IEEE transactions on 16 (1) 28-40 '                          |
|  2 | 'Data Engineering'               | '1999. Proceedings. 15th International Conference on 146-153' |
|  3 | 'ACM SIGMOD Record 30 (2)'       | '187-198'                                                     |

Answer 3

试试这个：

SELECT * FROM
    (
        SELECT ID, COLUMN1, COLUMN2, ROW_NUMBER() OVER 
        (PARTITION BY ID ORDER BY ID DESC) AS ROWID FROM YOUR_TABLE
    ) AS A
WHERE ROWID = 1

Answer 4

这个问题已经问了一百万次

使用cteDup AS（SELECT *，ROW_NUMBER（）OVER（按ID列分区ID排序）'Rank' 从表）

永久删除使用此

DELETE FROM cteDup
    WHERE Rank > 1

否则

select top 20 * from cteDup where Rownumber = 1

如何通过获取每个组中的最后一条记录来删除重复记录

4 个答案: