Using SQL derived tables  Subqueries using SQL derived tables

Chapter 9: SQL Derived Tables

Nesting

A query can use numerous nested derived table expressions, which are SQL expressions that define a SQL derived table. In the following example, the innermost derived table expression defines SQL derived table dt_1, the select from which forms the derived table expression defining SQL derived table dt_2.

select postalcode
   from (select postalcode
            from (select postalcode 
                    from authors) dt_1) dt_2

The degree of nesting is limited to 25.





Copyright © 2005. Sybase Inc. All rights reserved. Subqueries using SQL derived tables

View this book as PDF