SELECT OD.PaySource, (CASE WHEN FromMonth < 10 THEN CAST(FromMonth AS CHAR(1)) + 'm' ELSE (CASE WHEN FromMonth > 9 AND FromMonth 
< 12 THEN CAST(FromMonth AS CHAR(2)) + 'm' ELSE RTRIM(CAST(FromMonth / 12 AS CHAR(3)))  + 'y' END) END) + '-' + (CASE WHEN ToMonth < 12 THEN 
RTRIM(CAST(ToMonth AS CHAR(2))) + 'm' ELSE RTRIM(CAST(ToMonth / 12 AS CHAR(3))) + 'y' END) + ' ' + Sex AS Cat, Pts,Visits,ISNULL(FFS,0) AS FFS,((Amount / PtCount) * Pts) + 
ISNULL(FFS,0) AS CapFFS, ISNULL((Amount / PtCount) * Pts,0) AS Cap, CONVERT(DECIMAL(6,3),(Pts * 100.0) / (SELECT COUNT(DISTINCT PatID) FROM PatientIns WHERE InscoCode = OD.PaySource)) AS PctPts,
CONVERT(DECIMAL(6,3),(Visits * 100.0) / (SELECT COUNT(VoucherNo) FROM Vouchers WHERE Insco = OD.PaySource)) AS PctVisits,
ISNULL(((Amount / PtCount) * Pts + ISNULL(FFS,0)) / Visits,0) AS AvgTotVisit FROM
/*Problem is with the next two derived tables.  Separately, they run OK, when trying to JOIN them, get the error.  This error began after putting in the V derived table (see LEFT JOIN (Derived Table) V in the first outer derived table OD*/
(SELECT PtI.InscoCode AS Paysource,FromM AS FromMonth,ToM AS ToMonth, #Tbl.Sex, COUNT(DISTINCT PtI.PatID) AS Pts,COUNT(VoucherNo) AS Visits,SUM(TotPd) AS FFS 
FROM PatientIns PtI LEFT JOIN (SELECT VoucherNo,Patid,Insco,TotPd FROM Vouchers V WHERE (SELECT MAX(ServiceDate) FROM VouchersDetail WHERE Voucher = V.VoucherNo) BETWEEN
@Start AND @End) V ON V.PatID = PtI.Patid AND V.Insco = PtI.Inscocode INNER JOIN Patients P ON PtI.Patid = P.ID RIGHT JOIN #Tbl ON 
DATEDIFF(m,P.DOB,getdate()) BETWEEN #Tbl.FromM AND #Tbl.ToM AND P.Sex = (CASE WHEN #Tbl.Sex <> 'M' AND #Tbl.Sex <> 'F' THEN P.Sex ELSE #Tbl.Sex END)
WHERE PtI.Inscocode = @Insco GROUP BY InscoCode,FromM,ToM,#Tbl.Sex
UNION SELECT @Insco,FromM,ToM,Sex,0,0,NULL FROM #Tbl WHERE NOT EXISTS(SELECT * FROM Patients INNER JOIN PatientIns ON Patid = ID WHERE DATEDIFF(m,DOB,getdate()) BETWEEN #Tbl.FromM AND 
#Tbl.ToM AND Sex = (CASE WHEN #Tbl.Sex <> 'M' AND #Tbl.Sex <> 'F' THEN Sex ELSE #Tbl.Sex END)AND InscoCode = @Insco))OD
LEFT JOIN 
(SELECT PaySource,SUM(Amount) AS Amount,AVG(PtCount) AS PtCount,(SELECT COUNT(*) FROM Vouchers V INNER JOIN PatientIns P
ON P.Patid = V.Patid AND V.Insco = P.InscoCode WHERE Insco = OtherPmts.PaySource) AS TotVisits FROM OtherPmts WHERE PaySource = @Insco AND DtFrom BETWEEN @Start AND @End
GROUP BY PaySource)O ON O.PaySource = OD.Paysource 

(SELECT PtI.InscoCode AS Paysource,FromM AS FromMonth,ToM AS ToMonth, #Tbl.Sex, COUNT(DISTINCT PtI.PatID) AS Pts,COUNT(VoucherNo) AS Visits,SUM(TotPd) AS FFS 
FROM PatientIns PtI LEFT JOIN (SELECT VoucherNo,Patid,Insco,TotPd FROM Vouchers V WHERE (SELECT MAX(ServiceDate) FROM VouchersDetail WHERE Voucher = V.VoucherNo) BETWEEN
@Start AND @End) V ON V.PatID = PtI.Patid AND V.Insco = PtI.Inscocode INNER JOIN Patients P ON PtI.Patid = P.ID RIGHT JOIN #Tbl ON 
DATEDIFF(m,P.DOB,getdate()) BETWEEN #Tbl.FromM AND #Tbl.ToM AND P.Sex = (CASE WHEN #Tbl.Sex <> 'M' AND #Tbl.Sex <> 'F' THEN P.Sex ELSE #Tbl.Sex END)
WHERE PtI.Inscocode = @Insco GROUP BY InscoCode,FromM,ToM,#Tbl.Sex
UNION SELECT @Insco,FromM,ToM,Sex,0,0,NULL FROM #Tbl WHERE NOT EXISTS(SELECT * FROM Patients INNER JOIN PatientIns ON Patid = ID WHERE DATEDIFF(m,DOB,getdate()) BETWEEN #Tbl.FromM AND 
#Tbl.ToM AND Sex = (CASE WHEN #Tbl.Sex <> 'M' AND #Tbl.Sex <> 'F' THEN Sex ELSE #Tbl.Sex END)AND InscoCode = @Insco))OD

(SELECT PtI.InscoCode AS Paysource,FromM AS FromMonth,ToM AS ToMonth, #Tbl.Sex, COUNT(DISTINCT PtI.PatID) AS Pts,COUNT(DISTINCT VoucherNo) AS Visits,SUM(AmountPaid) AS FFS 
FROM PatientIns PtI LEFT JOIN Vouchers V ON V.PatID = PtI.Patid AND V.Insco = PtI.Inscocode LEFT JOIN Vouchersdetail VD
ON V.VoucherNo = VD.Voucher AND VD.ServiceDate BETWEEN @Start AND @End INNER JOIN Patients P ON PtI.Patid = P.ID RIGHT JOIN #Tbl ON 
DATEDIFF(m,P.DOB,getdate()) BETWEEN #Tbl.FromM AND #Tbl.ToM AND P.Sex = (CASE WHEN #Tbl.Sex <> 'M' AND #Tbl.Sex <> 'F' THEN P.Sex ELSE #Tbl.Sex END)
WHERE PtI.Inscocode = @Insco  GROUP BY InscoCode,FromM,ToM,#Tbl.Sex
UNION SELECT @Insco,FromM,ToM,Sex,0,0,NULL FROM #Tbl WHERE NOT EXISTS(SELECT * FROM Patients INNER JOIN PatientIns ON Patid = ID WHERE DATEDIFF(m,DOB,getdate()) BETWEEN #Tbl.FromM AND 
#Tbl.ToM AND Sex = (CASE WHEN #Tbl.Sex <> 'M' AND #Tbl.Sex <> 'F' THEN Sex ELSE #Tbl.Sex END)AND InscoCode = @Insco))OD