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 – 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. See the Transact-SQL User’s Guide.
An abstract plan derived table – 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.
