Alias Names for Fields
To enable easier manipulation of fields in the Dynamic Template Designer, a simpler name is assigned when a field is dragged into the Selected Fields panel in the Report Designer. This name, typically a single alpha character, can be used to perform operations, such as mathematical calculations, with other fields.
Note that as you add and remove fields from the selected list, the alphabetic sequence for the alias names is not retained. That is, when a field is removed, its alias name will not be reused when you add fields to the selected list.