A subquery is structured like a regular query.

In UltraLite, you can only use subquery references in the following situations:

You can write subqueries about names that are specified before (to the left of) the subquery, sometimes known as outer references to the left. However, you cannot have references to items within subqueries (sometimes known as inner references).

• SELECT statement [UltraLite]
• Use of subqueries
• Search conditions in UltraLite

The following subquery is used to list all product IDs for items that are low in stock (that is, less than 20 items).

FROM SalesOrderItems
 ( SELECT ID
   FROM Products
   WHERE Quantity < 20 );