Best data type to store money values in MySQL

Since money needs an exact representation don't use data types that are only approximate like float. You can use a fixed-point numeric data type for that like

decimal(15,2)

15 is the precision (total length of value including decimal places)

2 is the number of digits after decimal point

See MySQL Numeric Types:

These types are used when it is important to preserve exact precision, for example with monetary data.

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You can use DECIMAL or NUMERIC both are same

The DECIMAL and NUMERIC types store exact numeric data values. These types are used when it is important to preserve exact precision, for example with monetary data. In MySQL, NUMERIC is implemented as DECIMAL, so the following remarks about DECIMAL apply equally to NUMERIC. : MySQL

i.e. DECIMAL(10,2)

Good read

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I prefer to use BIGINT, and store the values in by multiply with 100, so that it will become integer.

For e.g., to represent a currency value of 93.49, the value shall be stored as 9349, while displaying the value we can divide by 100 and display. This will occupy less storage space.

Caution: Mostly we don't perform currency * currency multiplication, in case if we are doing it then divide the result with 100 and store, so that it returns to proper precision.

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It depends on your need.

Using DECIMAL(10,2) usually is enough but if you need a little bit more precise values you can set DECIMAL(10,4).

If you work with big values replace 10 with 19.

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If your application needs to handle money values up to a trillion then this should work: 13,2 If you need to comply with GAAP (Generally Accepted Accounting Principles) then use: 13,4

Usually you should sum your money values at 13,4 before rounding of the output to 13,2.

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At the time this question was asked nobody thought about Bitcoin price. In the case of BTC, it is probably insufficient to use DECIMAL(15,2). If the Bitcoin will rise to $100,000 or more, we will need at least DECIMAL(18,9) to support cryptocurrencies in our apps.

DECIMAL(18,9) takes 12 bytes of space in MySQL (4 bytes per 9 digits).

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We use double.

*gasp*

Why?

Because it can represent any 15 digit number with no constraints on where the decimal point is. All for a measly 8 bytes!

So it can represent:

0.123456789012345

123456789012345.0

...and anything in between.

This is useful because we're dealing with global currencies, and double can store the various numbers of decimal places we'll likely encounter.

A single double field can represent 999,999,999,999,999s in Japanese yens, 9,999,999,999,999.99s in US dollars and even 9,999,999.99999999s in bitcoins

If you try doing the same with decimal, you need decimal(30, 15) which costs 14 bytes.

Caveats

Of course, using double isn't without caveats.

However, it's not loss of accuracy as some tend to point out. Even though double itself may not be internally exact to the base 10 system, we can make it exact by rounding the value we pull from the database to its significant decimal places. If needed that is. (e.g. If it's going to be outputted, and base 10 representation is required.)

The caveats are, any time we perform arithmetic with it, we need to normalize the result (by rounding it to its significant decimal places) before:

Performing comparisons on it. Writing it back to the database.

Another kind of caveat is, unlike decimal(m, d) where the database will prevent programs from inserting a number with more than m digits, no such validations exists with double. A program could insert a user inputted value of 20 digits and it'll end up being silently recorded as an inaccurate amount.

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If GAAP Compliance is required or you need 4 decimal places:

DECIMAL(13, 4) Which supports a max value of:

$999,999,999.9999

Otherwise, if 2 decimal places is enough: DECIMAL(13,2)

src: https://rietta.com/blog/best-data-types-for-currencymoney-in/

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Indeed this relies on the programmer's preferences. I personally use: numeric(15,4) to conform to the Generally Accepted Accounting Principles (GAAP).

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Try using

Decimal(19,4)

this usually works with every other DB as well

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Storing money as BIGINT multiplied by 100 or more with the reason to use less storage space makes no sense in all "normal" situations.

To stay aligned with GAAP it is sufficient to store currencies in DECIMAL(13,4)

MySQL manual reads that it needs 4 bytes per 9 digits to store DECIMAL. https://dev.mysql.com/doc/refman/8.0/en/precision-math-decimal-characteristics.html

https://dev.mysql.com/doc/refman/8.0/en/precision-math-decimal-characteristics.html

DECIMAL(13,4) represents 9 digits + 4 fraction digits (decimal places) => 4 + 2 bytes = 6 bytes

compare to 8 bytes required to store BIGINT.

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Multiplies 10000 and stores as BIGINT, like "Currency" in Visual Basic and Office. See https://msdn.microsoft.com/en-us/library/office/gg264338.aspx

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