Creating Tables With Computed Columns

computed_column_expression can reference only columns in the same table.

The deterministic property of computed_column_expression significantly affects data operations. See Deterministic Property in the Transact-SQL Users Guide.

Computed columns cannot have default values, and cannot be identity or timestamp columns.

You can specify nullability only for materialized computed columns. If you do not specify nullability, all computed columns are, by default, nullable. Virtual computed columns are always nullable.

Triggers and constraints, such as check, rule, unique, primary key, or foreign key) support only materialized computed columns. You cannot use them with virtual computed columns.

If a user-defined function in a computed column definition is dropped or becomes invalid, any computed column operations that call that function fail.