Try something like that:
UPDATE t1 SET t1.transferbirds = t2.finalbirds
FROM K_RT_RetailsDetails AS t1 INNER JOIN (
select ROW_NUMBER() OVER(ORDER BY a.branch) as sno,b.sno as keys,
d.branch,a.transferbirds,b.noofbirds,c.noofbirds,e.mortality,
(a.transferbirds-b.noofbirds-c.noofbirds-e.mortality) as finalbirds
from K_RT_RetailsDetails a
inner join K_RT_WarehouseDetails b on a.branch = b.branch
inner join K_RT_MasterBirdsTransferDet c on a.branch = c.frombranch
inner join K_RT_MasterRetailStores d on d.sno = a.branch
inner join K_RT_DailyEntry e on e.branch = d.sno
where d.branch = @branch
) AS t2 ON t1.t1.KeyField = t2.KeyField
Note: Replace
KeyField
with Identity field (with uniqe values) in
K_RT_RetailsDetails
.