Editing Select (SQL) (section)

=== Derived table ===

A derived table is a subquery in a FROM clause. Essentially, the derived table is a subquery that can be selected from or joined to. Derived table functionality allows the user to reference the subquery as a table. The derived table also is referred to as an ''inline view'' or a ''select in from list''.

In the following example, the SQL statement involves a join from the initial Books table to the derived table "Sales".  This derived table captures associated book sales information using the ISBN to join to the Books table.  As a result, the derived table provides the result set with additional columns (the number of items sold and the company that sold the books):

<syntaxhighlight lang="sql">
SELECT b.isbn, b.title, b.price, sales.items_sold, sales.company_nm
FROM Book b
  JOIN (SELECT SUM(Items_Sold) Items_Sold, Company_Nm, ISBN
        FROM Book_Sales
        GROUP BY Company_Nm, ISBN) sales
  ON sales.isbn = b.isbn
</syntaxhighlight>