Question

我的表名为Customer，其中包含基于某些字段的重复记录 客户表：
CUST_ID
EMAIL_ID
ROLE_ID
DOB
CREATION_DATE

客户表中的

数据如下所示：

cust_id  email_id            role_id      dob        creation_date 
1        abc@abc.com            5       4/2/1966       17/09/2016   
2        abc@abc.com            5       4/2/1966       20/09/2016   
3        xyz@xyz.com            5       15/2/1991      18/09/2016  
4        xyz@xyz.com            5       15/2/1991      21/09/2016  
5        pqr@pqr.com            5       16/2/1985      30/09/2016   
6        pqr@pqr.com            5       16/2/1985      05/11/2016 
7        pqr@pqr.com            5       16/2/1985      04/11/2016

对于2条或更多条记录，email_id，role_id和dob相同（重复），如上表所示。

我想要两个不同的查询，结果如下：

cust_id  email_id            role_id      dob        creation_date 
1        abc@abc.com            5       4/2/1966       17/09/2016     
3        xyz@xyz.com            5       15/2/1991      18/09/2016   
5        pqr@pqr.com            5       16/2/1985      30/09/2016

即，删除基于email_id，role_id和dob的重复记录，其creation_date小于另一个重复记录。

cust_id  email_id            role_id      dob        creation_date   
2        abc@abc.com            5       4/2/1966       20/09/2016     
4        xyz@xyz.com            5       15/2/1991      21/09/2016   
6        pqr@pqr.com            5       16/2/1985      05/11/2016

即，删除基于email_id，role_id和dob的重复记录，其creation_date大于其他重复记录。

编辑：针对上述问题的反问题。

现在，当我连接两个名为Customer and Individual的表时，我将如何得到与上述相同的结果。
客户表：
CUST_ID
EMAIL_ID
ROLE_ID
individaul_id（外键）
creation_date

个性表：
individaul_id
dob

使用以下查询：

SELECT c.email_id,c.role_id,i.dob  FROM CUSTOMER c   
JOIN  INDIVIDUAL i on c.individaul_id=i.individaul_id     
GROUP BY c.email_id,c.role_id,i.dob     
Having count(*) >=2

我正在使用 MSSQL server 2012 数据库非常感谢提前。

Answer 1

您可以使用ROW_NUMBER（）按创建日期排序并过滤掉重复记录

第一个查询给出最小创建日期的记录

;WITH cte AS (
SELECT cust_id,  email_id, role_id, dob, creation_date ,
       ROW_NUMBER() OVER(PARTITION BY email_id, role_id, dob ORDER BY creation_date ) seq FROM customer
)
SELECT  cust_id,  email_id, role_id, dob, creation_date 
FROM cte
WHERE seq = 1

对于最大创建日期，同一查询使用ORDER BY按降序完成

 ;WITH cte AS (
    SELECT cust_id,  email_id, role_id, dob, creation_date ,
           ROW_NUMBER() OVER(PARTITION BY email_id, role_id, dob ORDER BY creation_date DESC ) seq FROM customer
    )
    SELECT  cust_id,  email_id, role_id, dob, creation_date 
    FROM cte
    WHERE seq = 1

修改对于JOIN查询，只需将连接条件添加到CTE表达式SELECT语句

;WITH cte AS ( SELECT c.cust_id, c.email_id, c.role_id, i.dob, c.creation_date , ROW_NUMBER() OVER(PARTITION BY c.email_id, c.role_id, c.dob ORDER BY c.creation_date ) seq FROM customer c JOIN INDIVIDUAL i on c.individaul_id=i.individaul_id ) SELECT cust_id, email_id, role_id, dob, creation_date FROM cte WHERE seq = 1

对于最大创建日期，同一查询使用ORDER BY按降序完成

;WITH cte AS ( SELECT c.cust_id, c.email_id, c.role_id, i.dob, c.creation_date , ROW_NUMBER() OVER(PARTITION BY c.email_id, c.role_id, c.dob ORDER BY c.creation_date DESC ) seq FROM customer c JOIN INDIVIDUAL i on c.individaul_id=i.individaul_id ) SELECT cust_id, email_id, role_id, dob, creation_date FROM cte WHERE seq = 1

Answer 2

使用最小和最大功能

select min(cust_id),email_id,role_id,dob,min(creation_date) from customer group by email_id,role_id,dob;

select max(cust_id),email_id,role_id,dob,max(creation_date) from customer group by email_id,role_id,dob;

希望它有效

Answer 3

您可以使用ROW_NUMBER和PARTITION来实现此目的。只需谷歌相同。

检查此查询：

    Declare @customer table(cust_id int, email_id varchar(200), role_id int, dob datetime, creation_date datetime)

    Insert into @customer
    values(1,'abc@abc.com',5,'04-feb-1966','17-sep-2016'),
    (2,'abc@abc.com',5,'04-feb-1966','20-sep-2016'),
    (3,'xyz@xyz.com',5,'15-feb-1991','18-sep-2016'),
    (4,'xyz@xyz.com',5,'15-feb-1991','21-sep-2016'),
    (5,'pqr@pqr.com',5,'16-feb-1985','30-sep-2016'),
    (6,'pqr@pqr.com',5,'16-feb-1985','05-nov-2016'),
    (7,'pqr@pqr.com',5,'16-feb-1985','04-nov-2016')

--using row number and partition to group data and remove duplicate
    ;with custCTE as(
    select cust_id, email_id, role_id,dob,creation_date,row_number() over(partition by email_id, role_id, dob order by creation_date ) as rnk
    from @customer
    )

    delete from @customer where cust_id in (select cust_id from custCTE where rnk <> 1)
    select * from @customer

Answer 4

这是解决方案。

DECLARE @MainTable TABLE
(
    Cust_Id INT,
    Email_Id NVARCHAR(250),
    Role_Id INT,
    DOB DATE,
    Creation_Date DATE 
)

DECLARE @Table1 TABLE
(
    Cust_Id INT,
    Email_Id NVARCHAR(250),
    Role_Id INT,
    DOB DATE,
    Creation_Date DATE 
)

DECLARE @Table2 TABLE
(
    Cust_Id INT,
    Email_Id NVARCHAR(250),
    Role_Id INT,
    DOB DATE,
    Creation_Date DATE 
)

INSERT INTO @MainTable
        ( Cust_Id ,
          Email_Id ,
          Role_Id ,
          DOB ,
          Creation_Date
        )
VALUES  ( 1 , N'abc@abc.com' , 5 , '2/4/1966' , '09/17/2016' ),
        ( 2 , N'abc@abc.com' , 5 , '2/4/1966' , '09/20/2016' ),
        ( 3 , N'xyz@xyz.com' , 5 , '2/15/1991' , '09/18/2016' ),
        ( 4 , N'xyz@xyz.com' , 5 , '2/15/1991' , '09/21/2016' ),
        ( 5 , N'pqr@pqr.com' , 5 , '2/16/1985' , '09/30/2016' ),
        ( 6 ,N'pqr@pqr.com' , 5 , '2/16/1985' , '11/05/2016' ),
        ( 7 , N'pqr@pqr.com' , 5 , '2/16/1985' , '11/04/2016' )

;WITH MainTable AS (
SELECT 
    Cust_Id ,
    Email_Id ,
    Role_Id ,
    DOB ,
    Creation_Date ,
    RANK() OVER (PARTITION BY Email_Id, Role_Id, DOB ORDER BY Creation_Date) AS [Rank]
FROM @MainTable
) 
INSERT INTO @Table1
SELECT 
    MainTable.Cust_Id ,
    MainTable.Email_Id ,
    MainTable.Role_Id ,
    MainTable.DOB ,
    MainTable.Creation_Date 
FROM MainTable
WHERE MainTable.[Rank] = 1

;WITH MainTable AS (
SELECT 
    Cust_Id ,
    Email_Id ,
    Role_Id ,
    DOB ,
    Creation_Date ,
    RANK() OVER (PARTITION BY Email_Id, Role_Id, DOB ORDER BY Creation_Date) AS [Rank]
FROM @MainTable
) 
INSERT INTO @Table2
SELECT 
    MainTable.Cust_Id ,
    MainTable.Email_Id ,
    MainTable.Role_Id ,
    MainTable.DOB ,
    MainTable.Creation_Date 
FROM MainTable
WHERE MainTable.[Rank] <> 1


SELECT * FROM @MainTable ORDER BY Cust_Id
SELECT * FROM @Table1 ORDER BY Cust_Id
SELECT * FROM @Table2 ORDER BY Cust_Id

基本上，使用sql server windows函数可以更好地处理这些问题。在具有添加功能的sql server 2012中，窗口函数功能更强大。因此，上面的代码在MSSQL 2012中可以正常工作。

Answer 5

我已经使用@navintb回答的查询并将其修改如下，以删除重复的结果，以便获得所需的输出。

SELECT max(cust_id),c.email_id,c.role_id,i.dob,max(creation_date) FROM 
CUSTOMER c 
JOIN INDIVIDUAL i on c.individual_id=i.individual_id
GROUP BY c.email_id,c.role_id,i.dob
Having count(*) >=2

和

SELECT min(cust_id),c.email_id,c.role_id,i.dob,min(creation_date) FROM 
CUSTOMER c 
JOIN INDIVIDUAL i on c.individual_id=i.individual_id
GROUP BY c.email_id,c.role_id,i.dob
Having count(*) >=2

根据某些字段（email_id，role_id和dob）并根据条件（creation_date）

5 个答案: