I agree, not sure why you would ever want the same data in another column; maybe you should make it null or add a placeholder, and then do some calculation and populate later?

You might do something like this?

DROP TABLE #example

GO

CREATE TABLE #example(exampleId int identity(1,1) NOT NULL PRIMARY KEY,

exampletext varchar(30),

myCalculatedField AS SUBSTRING (ExampleText, CHARINDEX(':', exampleText )+1, len(exampleText)),

myCalcd2 AS UPPER(LEFT(SUBSTRING (ExampleText, CHARINDEX(':', exampleText )+1, len(exampleText)),4))

)

GO

INSERT INTO #example (exampletext)

VALUES ('Product Description: Chair' )

GO

SELECT * FROM #example

GO