I don't want to embarrass the person who wrote this script. So, instead of sharing that person's link, the following is the script from that link:
select
CM.CUSTNMBR Customer_ID, CM.CUSTNAME Customer_Name,
CM.PYMTRMID Customer_Terms, CM.CUSTCLAS Customer_Class,
CM.PRCLEVEL Price_Level,
sum(case
when RM.RMDTYPAL < 7 then RM.CURTRXAM
else RM.CURTRXAM * -1
end) Total_Due,
sum(case
when DATEDIFF(d, RM.DUEDATE, getdate()) < 31
and RM.RMDTYPAL < 7 then RM.CURTRXAM
when DATEDIFF(d, RM.DOCDATE, getdate()) < 31
and RM.RMDTYPAL > 6 then RM.CURTRXAM *-1
else 0
end) [Current],
sum(case
when DATEDIFF(d, RM.DUEDATE, getdate()) between 31 and 60
and RM.RMDTYPAL < 7 then RM.CURTRXAM
when DATEDIFF(d, RM.DOCDATE, getdate()) between 31 and 60
and RM.RMDTYPAL > 6 then RM.CURTRXAM * -1
else 0
end) [31_to_60_Days],
sum(case
when DATEDIFF(d, RM.DUEDATE, getdate()) between 61 and 90
and RM.RMDTYPAL < 7 then RM.CURTRXAM
when DATEDIFF(d, RM.DOCDATE, getdate()) between 61 and 90
and RM.RMDTYPAL > 6 then RM.CURTRXAM * -1
else 0
end) [61_to_90_Days],
sum(case
when DATEDIFF(d, RM.DUEDATE, getdate()) > 90
and RM.RMDTYPAL < 7 then RM.CURTRXAM
when DATEDIFF(d, RM.DOCDATE, getdate()) > 90
and RM.RMDTYPAL > 6 then RM.CURTRXAM *-1
else 0
end) [91_and_Over],
CS.LASTPYDT Last_Payment_Date,
CS.LPYMTAMT Last_Payment_Amount
from RM20101 RM
inner join RM00101 CM
on RM.CUSTNMBR = CM.CUSTNMBR
inner join RM00103 CS
on RM.CUSTNMBR = CS.CUSTNMBR
where RM.VOIDSTTS = 0 and RM.CURTRXAM <> 0
group by CM.CUSTNMBR, CM.CUSTNAME, CM.PYMTRMID, CM.CUSTCLAS,
CM.PRCLEVEL, CS.LASTPYDT,CS.LPYMTAMT
