Oracle 18c

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create table xxng_supp_ledger (VENDOR_NAME varchar(20), DR  int, CR  int )
insert into xxng_supp_ledger values('VendorName_1', 10, 5)
1 rows affected

insert into xxng_supp_ledger values('VendorName_2', 100, 50)
1 rows affected

insert into xxng_supp_ledger values('VendorName_3', 20, 1)
1 rows affected

insert into xxng_supp_ledger values('VendorName_4', 40, 5)
1 rows affected

SELECT xsl.VENDOR_NAME
       , nvl(xsl.DR , 0) - nvl(xsl.CR , 0) Balance
       , ROW_NUMBER() OVER(ORDER BY  (nvl(xsl.DR , 0) - nvl(xsl.CR , 0)) desc) rank_max 
FROM xxng_supp_ledger xsl


VENDOR_NAME
BALANCE
RANK_MAX


VendorName_2
50
1

VendorName_4
35
2

VendorName_3
19
3

VendorName_1
5
4