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MS SQL Server - make column values unique
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In this article, we would like to show you how to make column values unique in MS SQL Server.
Quick solution:
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ALTER TABLE [table_name] 2
ADD UNIQUE ([column_name]);or
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ALTER TABLE [table_name]2
ADD CONSTRAINT [constraing_name] UNIQUE ([column1], [column2], [columnN]);To show how to make column values unique, we will use the following table:
In this example, we will make name column unique.
Query:
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ALTER TABLE [users]2
ADD CONSTRAINT [UC_username] UNIQUE ([name]);Result:
Using query
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SHOW INDEXES FROM [users];
Using HeidiSQL
In this example, we will make name and country columns unique.
Query:
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ALTER TABLE [users]2
ADD CONSTRAINT [UC_user] UNIQUE ([name], [country]);Result:
Using query
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SHOW INDEXES FROM [users];
Using HeidiSQL:
