How to remove duplicate data from a table?

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I have a table call EMP, which have 3 columns (EMP_NAME, EMP_MAIL, EMP_CONTACT) and does not have any primary key. Now i want to delete the duplicate row from this table using SQL inline query.

Below is the example.

emp_name emp_mail emp_contact

Arijita abcd@xyz 8122020706
Arijit abc@xy 8122020705
Arijit abc@xy 8122020705
Arijit abc@xy 8122020705

I search a query which will help me to delete the duplicate values.

Output should be :

emp_name || emp_mail || emp_contact

Arijita || abcd@xyz || 8122020706
Arijit || abc@xy || 8122020705

What I have tried:

I have found that how many duplicates are there.

Posted 28-Jul-16 9:45am

Bittu14

Updated 11-Aug-16 2:00am

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3 solutions

Solution 2

Take a look at these links
Removing Duplicates from a Table in SQL Server - Simple Talk
Delete duplicate rows in SQL Server

hope these links helps

Posted 28-Jul-16 19:49pm

Daniel Jones

Solution 3

;WITH CTE
AS
(
SELECT emp_name,emp_mail,emp_contact,ROW_NUMBER() OVER(PARTITION BY emp_name,emp_mail,emp_contact ORDER BY emp_name,emp_mail,emp_contact) AS No
FROM EMP
)
DELETE FROM CTE WHERE No > 1

Posted 11-Aug-16 2:00am

mansi chaudhari

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Suvendu Shekhar Giri · Accepted Answer · 2016-07-28T10:21:00

Solution 1

You can write a query for that something like following-

SQL

;WITH CTE(emp_name,emp_mail,emp_contact,SlNo)
AS
(
    SELECT emp_name,emp_mail,emp_contact,ROW_NUMBER() OVER(PARTITION BY emp_name,emp_mail,emp_contact ORDER BY emp_name,emp_mail,emp_contact) AS SlNo
    FROM Demo
)
DELETE FROM CTE WHERE SlNo > 1

For more details please visit my blog post at-
SQL Server: Delete/Update duplicate records | Technology Talks[^]

Hope, it helps :)

Posted 28-Jul-16 10:21am

Suvendu Shekhar Giri

Updated 28-Jul-16 10:33am

v3

Comments

Richard Deeming 28-Jul-16 16:29pm

If you specify the column aliases in the "header" of the CTE, you have to give an alias for all columns. You're currently missing SlNo.

Either:
WITH CTE(emp_name,emp_mail,emp_contact,SlNo) As ...

or:
WITH CTE As ...

would work.

Suvendu Shekhar Giri 28-Jul-16 16:35pm

Thanks Richard for pointing out the mistake.. updated the answer.

Karthik_Mahalingam 29-Jul-16 0:54am

5