Formula Field Sorting

Question

Frield 1 is group on Date (Group1)
Field 2 is group on workstation (Group 2)
Field 3 is a formula field Sum(Amt).
The Report will look like below when displaying the Group Footer #2 (workstation) line.
Date           Workstation    Amount
11/01/2010        A             2,550
11/01/2010        B            55,000
11/03/2010        D            78,200
11/04/2010        C              5,500
I would like to report to be sorted in decending order on the Amount field which is a formula field.
Date           Workstation    Amount
11/03/2010        D             78,200
11/01/2010        B            55,000
11/04/2010        C              5,500
11/01/2010        A              2,550
The Group Expert does not list the formula field as a field that can be grouped on. How can this be done?

Answer 1

Hi
I have a similar issue....
I have a report that's looking for Turnbacks,Total Trips and Turnback Percent of total trips grouped by Vendor.
Report Layout
Date (Group1)
Vendor (Group2)
Under group Vendor I have summarized fields...
Date 20101119
Vendor Id         Sum of Turnbacks         T otal Trips                      Turnback Percent of total Trips
123                   50                                  100                                       50%
456                  10                                  100                                       10%
789                  100                                100                                       100%
Date 20101120 
Vendor Id         Sum of Turnbacks         Total Trips                          Turnback Percent of total Trips
123                   60                                  100                                         60%
456                   20                                  100                                         20%
789                  100                                100                                         100%
I would like to sort the  Turnback Percent of total Trips field in descending order. But it does not appear in neither(Group or Record) sort option.
Any help will be greatly appreciated.
Thanks!