Aging of Accounts in SQL SERVER

Question

I need help from DBA's and from those who got a better knowledge of SQL SERVER.

 

I need to produce an aging of accounts. Below is my query and its result:

select SUM(e.TotalPremium) AS [SOLD POLICY],
    CASE
        WHEN DATEDIFF(D, e.DateIssued, getdate()) <= 30 THEN '30 Days'
        WHEN DATEDIFF(D, e.DateIssued, getdate()) <= 60 THEN '60 Days'
        WHEN DATEDIFF(D, e.DateIssued, getdate()) <= 90 THEN '90 Days'
        ELSE 'Above 90 days'
    END as AGING
from tblMotorInsurance_eCI e
where e.AgentID='16-113-01' and e.Remarks <> 'Cancel' and e.IsPaid = 'false'
group by e.DateIssued

 

As you can see from the result, I need to group them according to aging of accounts. Any help is really appreciated.