Final answer:
A virtual or computed column is a type of column in a database table whose value is calculated at the time of a query using data from other columns, and does not physically exist in the base table.
Step-by-step explanation:
The term you are looking for is a virtual column or computed column. A virtual or computed column does not physically exist within the base table. Instead, its value is calculated at the time of a query, using data from other columns. For example, in a database table with columns for first_name and last_name, you could have a computed column that concatenates these to form a full name each time a query runs that includes this column.
The value of a computed column is not stored with the rest of the row data; rather it is derived from an expression or function that uses the table's stored data when queried.