To define a new IDENTITY column in a select into statement, add the column definition before the into clause.
select column_list identity_column_name = identity(precision) into table_name from table_name
select *, id_col=identity(5) into new_discounts from discounts
If the column_list includes an existing IDENTITY column, and you add a description of a new IDENTITY column, the select into statement fails.
You cannot use the union operator with an identity function in a select into.