tblFeesGenerate
| AdmissionNo | FeesMonth | Total Fees | 
| R-001 | Aug | 700 | 
| R-002 | Aug | 700 | 
| R-003 | Aug | 700 | 
|  R-004 | Aug | 700 | 
| R-005 | Aug | 700 | 
| R-001 | Sep | 500 | 
| R-002 | Sep | 500 | 
| R-003 | Sep | 500 | 
|  R-004 | Sep | 500 | 
| R-005 | Sep | 500 | 
tblFeesCollection 
| AdmissionNo | NetBal | Paid | RemBal | FeesMonth | 
| R-001 | 700 | 500 | 200 | Aug | 
| R-002 | 700 | 400 | 300 | Aug | 
| R-003 | 700 | 350 | 350 | Aug | 
| R-004 | 700 | 700 | 0 | Aug | 
| R-005 | 700 | 700 | 0 | Aug | 
Required Defaulter List
| AdmissionNo | NetBal  (Previous Month Balance (Aug) + New Month generated Fees(Sep)) | Paid | RemBal | 
| R-001 | 200 + 500 | 0 | 700 | 
| R-002 | 300+500 | 0 | 800 | 
| R-003 | 350+500 | 0 | 850 | 
| R-004 | 500 | 0 | 500 | 
| R-005 | 500 | 0 | 500 | 
 
SELECT fc.AdmissionNo,ReferenceNo,SName,FName,ParentID,AcademicName,ClassName,SectionName,Year,SUM(Recievable) as [Recievable],SUM(NetBal) as [NetBal],SUM(Paid) as [Paid],SUM(RemBal) as [RemBal],FPhone 
FROM tblFeesCollection as fc inner join tblStdReg as sr on sr.AdmissionNo=fc.AdmissionNo inner join tblAcademicYear as ay on sr.YearID=ay.YearID inner join tblDefClass as dc on dc.ClassID=sr.ClassID 
inner join tblDefSection as ds on ds.SectionID=sr.SectionID 
where Year=@Year and Paid= 0 or RemBal > 0 and FeeID in (select max(FeeID) from tblFeesCollection group by AdmissionNo) 
GROUP BY fc.AdmissionNo,SName,FName,ParentID,Year,ReferenceNo,AcademicName,ClassName,SectionName,FPhone;
 
select fg.AdmissionNo,RemBal + sum(Head+ExamFees) 'Total',ISNULL((SELECT Paid FROM tblFeesCollection WHERE FeesMonth='8-Aug'),0) 'Paid'
,(RemBal + sum(Head+ExamFees)) - ISNULL ((SELECT Paid FROM tblFeesCollection WHERE FeesMonth='8-Aug'),0) as [RemBal]
from tblFeesGenerate as fg inner join tblFeesCollection as fc on fg.AdmissionNo=fc.AdmissionNo where fc.FeesMonth='8-Aug'
--and fg.AdmissionNo='R-000003'
group by fg.AdmissionNo,RemBal
it is showing the following error
Msg 512, Level 16, State 1, Line 4 Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.