Best data type for storing currency values in a MySQL database
Something like Decimal(19,4) usually works pretty well in most cases. You can adjust the scale and precision to fit the needs of the numbers you need to store. Even in SQL Server, I tend not to use "money" as it's non-standard.
The only thing you have to watch out for is if you migrate from one database to another you may find that DECIMAL(19,4) and DECIMAL(19,4) mean different things
( http://dev.mysql.com/doc/refman/5.1/en/precision-math-decimal-changes.html )
DBASE: 10,5 (10 integer, 5 decimal) MYSQL: 15,5 (15 digits, 10 integer (15-5), 5 decimal)
It is also important to work out how many decimal places maybe required for your calculations.
I worked on a share price application that required the calculation of the price of one million shares. The quoted share price had to be stored to 7 digits of accuracy.