SQLMenace说钱是不精确的。但是你不能把钱乘以/除以钱!3美元乘以50美分等于多少?150 dollarcents ?你用标量乘(除)钱，结果应该是小数。

DECLARE
@mon1 MONEY,
@mon4 MONEY,
@num1 DECIMAL(19,4),
@num2 DECIMAL(19,4),
@num3 DECIMAL(19,4),
@num4 DECIMAL(19,4)

SELECT
@mon1 = 100,
@num1 = 100, @num2 = 339, @num3 = 10000

SET @mon4 = @mon1/@num2*@num3
SET @num4 = @num1/@num2*@num3

SELECT @mon4 AS moneyresult,
@num4 AS numericresult

结果在正确的结果:

moneyresult           numericresult
--------------------- ---------------------------------------
2949.8525             2949.8525

钱是好的，只要你不需要超过4个十进制数字，你要确保你的标量(不代表钱)是小数。

我刚看到这个博客:SQL Server中的金钱vs.十进制。

这基本上是说金钱有一个精确的问题……

declare @m money
declare @d decimal(9,2)

set @m = 19.34
set @d = 19.34

select (@m/1000)*1000
select (@d/1000)*1000

对于货币类型，你将得到19.30而不是19.34。我不确定是否存在将钱分成1000份进行计算的应用场景，但这个示例确实暴露了一些局限性。

我找到了在精确度科目中使用十进制而不是货币的原因。

DECLARE @dOne   DECIMAL(19,4),
        @dThree DECIMAL(19,4),
        @mOne   MONEY,
        @mThree MONEY,
        @fOne   FLOAT,
        @fThree FLOAT

 SELECT @dOne   = 1,
        @dThree = 3,    
        @mOne   = 1,
        @mThree = 3,    
        @fOne   = 1,
        @fThree = 3

 SELECT (@dOne/@dThree)*@dThree AS DecimalResult,
        (@mOne/@mThree)*@mThree AS MoneyResult,
        (@fOne/@fThree)*@fThree AS FloatResult

十进制结果 > 1.000000

MoneyResult > 0.9999

FloatResult > 1

只需测试一下，然后做出决定。

作为对其他答案主旨的反驳。看金钱的诸多好处…数据类型!在SQLCAT的关系引擎指南中

我要具体指出以下几点

Working on customer implementations, we found some interesting performance numbers concerning the money data type. For example, when Analysis Services was set to the currency data type (from double) to match the SQL Server money data type, there was a 13% improvement in processing speed (rows/sec). To get faster performance within SQL Server Integration Services (SSIS) to load 1.18 TB in under thirty minutes, as noted in SSIS 2008 - world record ETL performance, it was observed that changing the four decimal(9,2) columns with a size of 5 bytes in the TPC-H LINEITEM table to money (8 bytes) improved bulk inserting speed by 20% ... The reason for the performance improvement is because of SQL Server’s Tabular Data Stream (TDS) protocol, which has the key design principle to transfer data in compact binary form and as close as possible to the internal storage format of SQL Server. Empirically, this was observed during the SSIS 2008 - world record ETL performance test using Kernrate; the protocol dropped significantly when the data type was switched to money from decimal. This makes the transfer of data as efficient as possible. A complex data type needs additional parsing and CPU cycles to handle than a fixed-width type.

所以这个问题的答案是“视情况而定”。对于某些算术操作，您需要更加小心，以保持精度，但您可能会发现，出于性能考虑，这样做是值得的。

我们刚刚遇到了一个非常相似的问题，我现在非常+1，因为除了在顶级演示中，我从不使用Money。我们有多个表(实际上是一个销售凭证和一个销售发票)，由于历史原因，每个表都包含一个或多个Money字段，我们需要按比例计算出总发票中有多少Tax与销售凭证上的每一行相关。我们的计算是

vat proportion = total invoice vat x (voucher line value / total invoice value)

这将导致现实世界中的货币/货币计算，从而导致在分割部分上的刻度错误，然后乘以一个不正确的增值税比例。当这些价值随后相加时，我们最终得到的是增值税比例的总和，加起来不等于发票总价值。如果括号中的任何一个值是小数(我将把其中一个转换为小数)，vat比例将是正确的。

当括号不存在的时候，原来这是工作的，我猜是因为涉及到更大的值，它有效地模拟了一个更高的规模。我们添加括号是因为它先做乘法运算，这在一些罕见的情况下会破坏计算的精度，但这现在已经导致了这个更常见的错误。

基于我个人的专业知识和经验，我想对金钱和数值给出不同的看法。我的观点是金钱，因为我已经用了很长一段时间，从来没有真正使用数值…

资金支持:

Native Data Type. It uses a native data type (integer) as the same as a CPU register (32 or 64 bit), so the calculation doesn't need unnecessary overhead so it's smaller and faster... MONEY needs 8 bytes and NUMERICAL(19, 4) needs 9 bytes (12.5% bigger)... MONEY is faster as long as it is used for it was meant to be (as money). How fast? My simple SUM test on 1 million data shows that MONEY is 275 ms and NUMERIC 517 ms... That is almost twice as fast... Why SUM test? See next Pro point Best for Money. MONEY is best for storing money and do operations, for example, in accounting. A single report can run millions of additions (SUM) and a few multiplications after the SUM operation is done. For very big accounting applications it is almost twice as fast, and it is extremely significant... Low Precision of Money. Money in real life doesn't need to be very precise. I mean, many people may care about 1 cent USD, but how about 0.01 cent USD? In fact, in my country, banks no longer care about cents (digit after decimal comma); I don't know about US bank or other country...

钱反对:

有限的精度。MONEY只有四位数(在逗号之后)精度，所以在进行除法等运算之前必须对其进行转换…但话又说回来，钱不需要这么精确，它是作为货币使用的，而不仅仅是一个数字……

但是…很大，但这里甚至是您的应用程序涉及到真钱，但不要在很多SUM操作中使用它，比如在会计中。如果你用了很多除法和乘法，那么你就不应该用MONEY…