Question

我进行计算,我没有获得我期望的答案。我失去了计算方法的一些比额表。

Calc is: 651/1000 * - 413.72063274 = - 269.33213191 (to 8 d.p)

联合国我这样做:

declare @var numeric(28,8)
declare @a numeric(28,8)
declare @b numeric(28,8)

set @var = -413.72063274
set @a   = 651.00000000
set @b   = 1000.00000000

select CAST((@a/@b) * @var as numeric(28,8)) as result_1
     , CAST(CAST(@a as numeric(28,8)) 
      /CAST(@b as numeric(28,8)) as numeric(28,8)) 
      *CAST(@var as numeric (28,8))   as result_2

结果是

result_1: -269.33213200 (correct to 6dp)
result_2 : -269.332132 (correct to 6dp)

我如何回来:-269.33213191(更正为8dp)?

Answer 1

For this specific case, you could cheat by first multiplying all values and dividing the final result back with this multiplier.

declare @var numeric(28,8)
declare @a numeric(28,8)
declare @b numeric(28,8)
declare @m numeric(28,8)

set @var = -413.72063274
set @a   = 651.00000000
set @b   = 1000.00000000
set @m   = 10000000


select CAST(((@a*@m) * (@var*@m) / (@b*@m)) AS NUMERIC(28, 8)) / @m 
-- Result: -269.3321319137

<><>Edit>/strong>

另一方面,在保持其准确性而不使用乘数的情况下,

select CAST(@a * @var AS NUMERIC(28, 8)) / @b
-- Result: -269.3321319140

Answer 2

。

*The result precision and scale have an absolute maximum of 38. When a result precision is greater than 38, the corresponding scale is reduced to prevent the integral part of a result from being truncated.

但没有确切说明这种拖网是如何进行的。页: 1 然而,有时使用审判和错误更容易!

以下中间派系给你预期的结果。你们能否与他们一起生活?

DECLARE @var NUMERIC(19,8)
DECLARE @a NUMERIC(19,8)
DECLARE @b NUMERIC(19,8)

SET @var = -413.72063274
SET @a   = 651.00000000
SET @b   = 1000.00000000

DECLARE @v SQL_VARIANT 
SET @v =  CAST(@a/@b AS NUMERIC(24,10))* CAST(@var AS NUMERIC(23,8))

SELECT    CAST(SQL_VARIANT_PROPERTY(@v,  BaseType ) AS VARCHAR(30)) AS BaseType,    
          CAST(SQL_VARIANT_PROPERTY(@v,  Precision ) AS INT) AS PRECISION,    
          CAST(SQL_VARIANT_PROPERTY(@v,  Scale ) AS INT) AS Scale

Answer 3

你们先是分裂,然后又越多。精确度的损失在该司。这四舍五入到八分之八,结果乘以3位数(413)价值(最后两位数失踪)

解决办法是提高中间成果的精确度,或首先实现你的多重复。

(@a * @var) / @b)在数学上等同于您的计算,但可以得出更准确的结果。

友情链接