Question

我需要从我的员工表中删除重复项，但是如果重复项以相同的公司名称出现，则应将其保留。

我有以下数据

    empid       resource        Dpart        company
   111          alex             AA            1C
   112          chris            QA            2F
   111          alex             AA            1C 
   111          alex             AA            2F
   111          alex             AA            2F
   111          alex             AA            5F

我尝试了row_number（）over（partition），但是没有给出我期望的结果。请帮助我们。

 delete  duplicates from (SELECT empid, 
 resouces,department ,ROW_NUMBER() OVER  (PARTITION BY  empid, 
 resouces,departmentORDER BY empid) cnt FROM 
 (select empid, resouces,department from Employee )t1)  
 duplicates    WHERE duplicates.Cnt > 1

根据以上数据，重复删除员工表后

   empid       resource        Dpart        company
   111          alex             AA            1C
   112          chris            QA            2F
   111          alex             AA            1C

Answer 1

我认为您需要DENSE_RANK()代替：

DELETE e
FROM (SELECT e.*,
             DENSE_RANK() OVER (PARTITION BY empid, resource, Dpart ORDER BY company) AS Seq
      FROM Employee e
     ) e
WHERE e.Seq > 1;

Answer 2

使用dense_rank

with cte as
(
select *,dense_rank() over(partition by empid order by company) as rn
from Employee
)delete from cte where rn>1

Demo link

Answer 3

下面我举一个例子：

-创建表格

CREATE TABLE dbo.DiaChiEmail(
ID INT IDENTITY PRIMARY KEY,
Email VARCHAR(100),
Ten NVARCHAR(100)
)
GO

-插入一些记录

INSERT dbo.DiaChiEmail(Email,Ten)
 SELECT 'abc@gmail.com', 'abc' UNION ALL -- #1
 SELECT 'def@yahoo.com', 'def' UNION ALL -- #2
 SELECT 'ghi@hotmail.com', 'ghi' UNION ALL -- #3
 SELECT 'jkl@ymail.com', 'jkl' UNION ALL -- #4
 SELECT 'abc@gmail.com', 'abc 2' UNION ALL -- #5, dupl with #1
 SELECT 'abc@gmail.com', 'abc 3' UNION ALL -- #6, dupl with #1
 SELECT 'ghi@hotmail.com', 'ghi 2' -- #7, dupl with ghi #3

要删除重复记录的查询是：

WITH [TBL_DUPLICATE] AS
(
  SELECT
   STT = ROW_NUMBER() OVER (PARTITION BY Email ORDER BY ID DESC), Email
   FROM DiaChiEmail
    )
DELETE FROM [TBL_DUPLICATE] WHERE STT > 1

需要从表中查找和删除重复记录

3 个答案: