Group and Summarize Invoice Results by the Number of Days Open

To search for invoices, group and summarize the results by the number of days open (<31, 31-60, 60-89, and >=90), create a Transaction Saved Search and perform the following:
    1.    Navigate to Lists > Search > Saved Searches > New.
    2.    Click Transaction. 
    3.    Under Criteria tab and Standard subtab, set the following: 
         o    Type = Invoice
         o    Main Line = Yes 
    4.    Under Results tab and Columns subtab, set the following: 
         o    Formula (Text), Summary Type = Grouped, enter Formula:
            case 

when {daysopen} < 30 then '<30'
            when {daysopen} >= 30 and {daysopen} < 60 then '30 to 60'
            when {daysopen} >= 60 and {daysopen} < 90 then '60 to 90'
            else '>=90' END
·         Add the Number field and use summary type Count.

5. Cilck Save & Run.