Best way to store currency values on MySql database
Do not use FLOAT or DOUBLE.  If it is a single currency, then use DECIMAL(m,n) with m and n suitably chosen.  If different currencies are stored in the same column, values for m and n become messy.  And you can run into rounding issues -- because of different laws.

DECIMAL goes through a package that does INT-like stuff transparently.  DECIMAL(19,4) will be stored in

6 digits in (effectively) a `MEDIUMINT` (high-order digits)
9 digits in (effectively) a `INT`
4 digits in (effectively) a `SHORTINT`  (after the decimal point)