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MS SQL Server - find duplicated values
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In this article, we would like to show you how to find duplicated values in MS SQL Server.
Quick solution:
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SELECT [column_name], COUNT([column_name])2
FROM [table_name]3
GROUP BY [column_name]4
HAVING COUNT([column_name]) > 1;To show how to find duplicated values, we will use the following table:
Note:
At the end of this article you can find database preparation SQL queries.
In this example, we will display the number of names that are duplicated in users table.
Query:
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SELECT [name], COUNT([name]) AS 'name_number'2
FROM [users]3
GROUP BY [name]4
HAVING COUNT([name]) > 1;Result:
create_tables.sql file:
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CREATE TABLE [users] (2
[id] INT IDENTITY(1,1),3
[name] VARCHAR(100) NOT NULL,4
[email] VARCHAR(100) NOT NULL,5
[country] VARCHAR(15) NOT NULL,6
PRIMARY KEY ([id])7
);insert_data.sql file:
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INSERT INTO [users]2
([name], [email], [country])3
VALUES4
('Tom', 'tom1@email.com', 'Poland'),5
('Tom', 'tom2@email.com', 'Poland'),6
('Tom', 'tom3@email.com', 'Poland'),7
('Kim', 'kim1@email.com', 'Vietnam'),8
('Kim', 'kim2@email.com', 'Vietnam'),9
('Chris', 'chris1@email.com', 'Spain'),10
('Chris', 'chris2@email.com', 'Spain'),11
('Chris', 'chris3@email.com', 'USA');