Monday, April 06, 2009

Computed Columns in SQL Server 2005

A computed column is computed from an expression that can use other columns in the same table. The expression can be a noncomputed column name, constant, function, variable, and any combination of these connected by one or more operators. The expression cannot be a subquery.

For example, in the AdventureWorks sample database, the TotalDue column of the Sales.SalesOrderHeader table has the definition: TotalDue AS Subtotal + TaxAmt + Freight.