Derived Table is a sub-query used as a datasource for the main query.
To add a derived table, right click on the Query Building Area and select Add Derived Table from the context menu.
Adding a derived table
A new object representing the newly created derived table will be added to the query building area, and a tab will be created for it. This tab allows you to build it visually in the same way as the main query. Another way is to right click on the caption of an object representing the derived table and select the "Switch to derived table" item from context menu.
You may set an alias for a derived table in the same way as for an ordinary database object.
You may always get back to the main query and switch to any sub-query or derived table using tabs above the Query Building Area or by using the Query Structure Tree.
Getting access to a derived table