Add a column to a table with a default value equal to the value of an existing column

Question

How to add a column to a SQL Server table with a default value that is equal to value of an existing column?

I tried this T-SQL statement:

ALTER TABL         


        

Answer 1

You can use computed column to insert new column in a table based on an existing column value

ALTER TABLE dbo.TableName ADD NewColumn AS (OldColumn) PERSISTED;

OR, if you want to make some changes to the value based on existing column value, use

ALTER TABLE dbo.TableName ADD NewColumn AS (OldColumn * 1.5) PERSISTED;