BUG: Negative Zero on Some Multiplications of Decimal or Numeric Values

MORE INFORMATION

The SELECT statements given below illustrate the behavior. The last two SELECT statements (where the values are calculated) reveal that the returned value's sign is affected by the ordering of the parentheses.

 declare
         @a decimal(13,2),
         @b decimal(13,2),
         @c decimal(13,2),
         @d decimal(13,2)    /* This is the same equation as used to
                                calculate @a but multiplied by 1.00  */ 

   select
      @a=(-0.0)*(-0.0) , @b = (-0.00) * (-0.0),
      @c = (-0.0) * (-0.00), @d = 1.00 * (-0.0)*(-0.0)
   select @a, @b, @c, @d

   select
      @a=(-1.0)*(-0.0), @b = (-1.00)*(-0.0),
      @c = (-1.0)*(-0.00), @d = 1.00 * (-1.0)*(-0.0)
   select @a, @b, @c, @d

   select
      @a= -0.0*(-0.0), @b = -0.00 *(-0.0),
      @c = -0.0 * (-0.00), @d = 1.00 * -0.0*(-0.0)
   select @a, @b, @c, @d

   select
      @a= (-0.0)*-0.0, @b = (-0.00)*-0.0,
      @c = (-0.0)*-0.00, @d = 1.00 * (-0.0)*-0.0
   select @a, @b, @c, @d
				

Results:

   @A                @B                @C                @D
   ----------------- ----------------- ----------------- -----------------
   0.00              0.00              0.00              0.00

   ----------------- ----------------- ----------------- -----------------
   -0.00             0.00              0.00              0.00

   ----------------- ----------------- ----------------- -----------------
   0.00              0.00              0.00              0.00

   ----------------- ----------------- ----------------- -----------------
   -0.00             0.00              0.00              0.00