Should you choose the MONEY or DECIMAL(x,y) datatypes in SQL Server?

I'm curious as to whether or not there is a real difference between the money datatype and something like decimal(19,4) (which is what money uses internally, I believe).

I'm aware that money is specific to SQL Server. I want to know if there is a compelling reason to choose one over the other; most SQL Server samples (e.g. the AdventureWorks database) use money and not decimal for things like price information.

Should I just continue to use the money datatype, or is there a benefit to using decimal instead? Money is fewer characters to type, but that's not a valid reason :)

Solution 1:

Never ever should you use money. It is not precise, and it is pure garbage; always use decimal/numeric.

Run this to see what I mean:

DECLARE
    @mon1 MONEY,
    @mon2 MONEY,
    @mon3 MONEY,
    @mon4 MONEY,
    @num1 DECIMAL(19,4),
    @num2 DECIMAL(19,4),
    @num3 DECIMAL(19,4),
    @num4 DECIMAL(19,4)

    SELECT
    @mon1 = 100, @mon2 = 339, @mon3 = 10000,
    @num1 = 100, @num2 = 339, @num3 = 10000

    SET @mon4 = @mon1/@mon2*@mon3
    SET @num4 = @num1/@num2*@num3

    SELECT @mon4 AS moneyresult,
    @num4 AS numericresult

Output: 2949.0000 2949.8525

To some of the people who said that you don't divide money by money:

Here is one of my queries to calculate correlations, and changing that to money gives wrong results.

select t1.index_id,t2.index_id,(avg(t1.monret*t2.monret)
    -(avg(t1.monret) * avg(t2.monret)))
            /((sqrt(avg(square(t1.monret)) - square(avg(t1.monret))))
            *(sqrt(avg(square(t2.monret)) - square(avg(t2.monret))))),
current_timestamp,@MaxDate
            from Table1 t1  join Table1 t2  on t1.Date = traDate
            group by t1.index_id,t2.index_id

Solution 2:

SQLMenace said money is inexact. But you don't multiply/divide money by money! How much is 3 dollars times 50 cents? 150 dollarcents? You multiply/divide money by scalars, which should be decimal.

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

Results in the correct result:

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

money is good as long as you don't need more than 4 decimal digits, and you make sure your scalars - which do not represent money - are decimals.