declare @Original decimal( 10, 5 ),

        @Working  decimal( 15, 5 ), -- 10 + 5 = 15

        @Result   decimal( 15, 0 ); -- Doesn't need scale, only precision

Set @Original = 1078.734;   -- This would be, say, an input parameter

-- First, make a copy into the working variable capable of handling it.

Set @Working = @Original;

-- Now set up the loop

Set @Result = Floor( @Working );

While @Result < @Working

  begin

    Set @Working = @Working * 10;

    Set @Result  = floor( @Working );

  end--while

select  @Result as Result, @Working as Working;