Скачать или смотреть Remove Duplicate Rows In SQL | Very Population Question| Most Simple Explanation| MUST WATCH!!!

In this video, Removing Duplicate Concept is explained with example in a way you can never forget.

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To delete CustomerId from original table in Method 2 ,you can use below query:-

WITH CTE AS
(
SELECT CustomerId,FirstName,LastName,Gender FROM
(
SELECT *
,ROW_NUMBER() OVER(PARTITION BY FirstName,LastName,Gender ORDER BY CustomerId DESC) AS RNK
FROM Customer
)a
WHERE a.RNK=1
)

DELETE FROM Customer
WHERE CustomerId NOT IN
(
SELECT CustomerId FROM CTE
)



DDL & DML Script:-

DROP TABLE IF EXISTS Customer
CREATE TABLE Customer
(
CustomerId INT IDENTITY(1,1),
FirstName VARCHAR(100),
LastName VARCHAR(100),
Gender VARCHAR(100)
)

TRUNCATE TABLE Customer
INSERT INTO Customer
VALUES
('Amit','Singh','M'),
('Komal','Das','F'),
('Komal','Das','F'),
('Komal','Das','F'),
('Mukul','Kumar','M'),
('Krishna','Murthy','M'),
('Mukul','Kumar','M'),
('Krishna','Murthy','M'),
('Gaurab','Chauhan','M')