Здравствуйте, Sinclair, Вы писали:
P.S.
Исследовать поведение автовывода типов удобно при помощи вспомогательной процедуры:

IF OBJECT_ID (N'dbo.Analyse') IS NOT NULL
    DROP PROCEDURE dbo.Analyse;
GO
create procedure Analyse(@what sql_variant)
as 
begin
  print cast(@what as varchar(max))

  print
    cast(SQL_VARIANT_PROPERTY(@what, 'BaseType') as varchar(max)) +'('+
    cast(SQL_VARIANT_PROPERTY(@what, 'Precision') as varchar(max))+ ', ' +
    cast(SQL_VARIANT_PROPERTY(@what, 'Scale') as varchar(max)) + ')'
end
go

DECLARE 
  @foo decimal(19,2) = 41761414.14, 
  @bar decimal(19,2) = 42183246.61, 
  @what sql_variant
set @what = @foo / @bar * 100
exec Analyse @what

print cast(41761414.14 as dec(19, 2)) * 100 / cast(42183246.61 as dec(19,2))