Adding formula fields to a query

Besides the table columns, you can also add some formula fields to a query.

To add a formula field to a query:

In the Query Editor window, click Column > Add Formula Field on the menu bar.
In the Add Formula Field dialog, choose the required formula in the Formulas box and then click Add. The formula will then be placed into the criteria panel in the lower part of the Query Editor, which means that you can reference the formula in the query.
Repeat the above step until you have added all the required formula fields, and then click Close. The formulas are added to the current query.

Notes:

When you add a formula field, if the table that contains the field doesn't exist in the query, this table will be automatically added to the query.
You are not able to edit a formula in the Add Formula Field dialog.
After a formula field has been added to a query, if you want to replace it with another one, you can double-click its name in the criteria panel, and then choose the required field in the Replace Formula dialog.