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。

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。

You shouldn't use money when you need to do multiplications / divisions on the value. Money is stored in the same way an integer is stored, whereas decimal is stored as a decimal point and decimal digits. This means that money will drop accuracy in most cases, while decimal will only do so when converted back to its original scale. Money is fixed point, so its scale doesn't change during calculations. However because it is fixed point when it gets printed as a decimal string (as opposed to as a fixed position in a base 2 string), values up to the scale of 4 are represented exactly. So for addition and subtraction, money is fine.

小数点内部以10为底表示，因此小数点的位置也以10为底数为基础。这使得它的小数部分准确地代表了它的值，就像货币一样。不同之处在于十进制的中间值可以保持38位的精度。

对于浮点数，值以二进制形式存储，就像它是一个整数一样，并且小数点(或二进制，嗯，)点的位置相对于表示该数字的位。因为它是一个二进制小数点，以10为基数的数字在小数点后失去精度。1/5，或0.2，不能用这种方式精确地表示。货币和十进制都不受这个限制。

将货币转换为十进制，执行计算，然后将结果值存储回货币字段或变量中，这非常简单。

从我的角度来看，我希望发生在数字上的事情不需要太多思考就能发生。如果所有的计算都要转换成十进制，那么对我来说，我只想用十进制。我会保留money字段用于显示。

就尺寸而言，我看不出有多大差别来改变我的想法。Money需要4 - 8个字节，而decimal可以是5、9、13和17。9个字节可以覆盖8个字节的货币所能覆盖的全部范围。索引方面(比较和搜索应该具有可比性)。

我意识到WayneM已经声明他知道钱是特定的SQL Server。然而，他问是否有任何理由使用货币而不是十进制，反之亦然，我认为一个明显的原因仍然应该说明，那就是使用十进制意味着如果你不得不改变你的DBMS，它可以减少一件担心的事情——这是可能发生的。

使您的系统尽可能灵活!

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…

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。