list_view_kala را به صورت زیر اصلاح کنید
SELECT
dbo.kala.code_kala,
dbo.kala.name_kala,
dbo.vahed_kala.name_vk,
ISNULL(SUM(dbo.input_kala.tedad), 0) AS tedad
FROM
dbo.input_kala RIGHT OUTER JOIN
dbo.kala ON dbo.input_kala.code_kala = dbo.kala.code_kala LEFT OUTER JOIN
dbo.vahed_kala ON dbo.input_kala.code_vk = dbo.vahed_kala.code_vk
GROUP BY dbo.kala.code_kala, dbo.kala.name_kala, dbo.vahed_kala.name_vk
کوئری را هم به صورت زیر اصلاح کنید (فقط تابع isnull اضافه شده)
select
list_view_kala.code_kala,
list_view_kala.name_kala,
list_view_kala.name_vk,
(list_view_kala.tedad - isnull(sum(exit_kala.tedad) , 0)) as tedad
from list_view_kala
LEFT OUTER JOIN exit_kala
on list_view_kala.code_kala=exit_kala.code_kala
group by list_view_kala.code_kala,list_view_kala.tedad,list _view_kala.name_kala,list_view_kala.name_vk
order by list_view_kala.code_kala