Смело быть скучным (и поздно к партии).
declare @Modulus as Int = 7
declare @Samples as Table ( Value Int )
insert into @Samples ( Value ) values ( -12 ), ( -3 ), ( 0 ), ( 3 ), ( 13 ), ( 70 )
select Value,
case Sign( Value )
when 1 then Value % @Modulus
when -1 then Value % @Modulus + @Modulus
else 0
end as Modulus
from @Samples