Duplicate a Column in SQL Server

Here’s a very simple but useful post that shows how to duplicate an existing column in SQL Server.

Assuming we have the following table structure with data:

CREATE TABLE #TmpTable(ColA varchar(10))
INSERT INTO #TmpTable SELECT 'ValueOne'
INSERT INTO #TmpTable SELECT 'ValueTwo'
INSERT INTO #TmpTable SELECT 'ValueThree'
INSERT INTO #TmpTable SELECT 'ValueFour'
INSERT INTO #TmpTable SELECT 'ValueFive'
INSERT INTO #TmpTable SELECT 'ValueSix'

Now to duplicate ColA, use the following code:

ALTER TABLE #TmpTable
ADD ColB varchar(10)
GO

UPDATE #TmpTable
SET ColB = ColA
GO

SELECT * FROM #TmpTable

As you can see, we have added a new column to the Table and used a simple Update statement to duplicate ColA. If the column already exists, you can avoid the ALTER TABLE.

OUTPUT

About The Author

Suprotim Agarwal, MCSD, MCAD, MCDBA, MCSE, is the founder of DotNetCurry, DNC Magazine for Developers, SQLServerCurry and DevCurry. He has also authored a couple of books 51 Recipes using jQuery with ASP.NET Controls and a new one recently at The Absolutely Awesome jQuery CookBook.

Suprotim has received the prestigous Microsoft MVP award for nine times in a row now. In a professional capacity, he is the CEO of A2Z Knowledge Visuals Pvt Ltd, a digital group that represents premium web sites and digital publications comprising of Professional web, windows, mobile and cloud developers, technical managers, and architects.

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