A derived table is defined by the evaluation of a query expression and differs from a regular table in that it is neither described in system catalogs nor stored on disk. In Adaptive Server, a derived table may be a SQL derived table or an abstract plan derived table.
A SQL derived table is defined by one or more tables through the evaluation of a query expression. A SQL derived table is used in the query expression in which it is defined and exists only for the duration of the query. For more information on SQL derived tables, see the Transact-SQL User’s Guide.
An abstract plan derived table is a derived table used in query processing, the optimization and execution of queries. An abstract plan derived table differs from a SQL derived table in that it exists as part of an abstract plan and is invisible to the end user.
