select

t4.POID po_main_id,
t3.ID po_detail_id,
t4.cPOID po_code,

t2.ID arr_main_id,
t1.Autoid arr_detail_id,

po_vendor.cVenName po_vendor,
arr_vendor.cVenName arr_vendor,
t1.cInvCode

from PU_ArrivalVouchs t1

LEFT JOIN PU_ArrivalVouch t2
on t1.ID=t2.ID

LEFT JOIN PO_Podetails t3
on t1.iPOsID = t3.ID

LEFT JOIN PO_Pomain t4
on t3.POID=t4.POID

LEFT JOIN Vendor po_vendor
on po_vendor.cVenCode=t4.cVenCode

LEFT JOIN Vendor arr_vendor
on arr_vendor.cVenCode=t2.cVenCode

where t4.cVenCode!=t2.cVenCode