For optimum storage, you should try to use the most precise type in all cases. For example, if an integer column
is used for values in the range from
MEDIUMINT UNSIGNED is the best type. Of the types that represent all the required
values, this type uses the least amount of storage.
If accuracy is not too important or if speed is the highest priority, the
DOUBLE type may be good enough. For high precision, you can always convert to a
fixed-point type stored in a
BIGINT. This enables you to do all calculations with 64-bit integers and then
convert results back to floating-point values as necessary.
PROCEDURE ANALYSE can be used to obtain suggestions for optimal column data types.
For more information, see Section 188.8.131.52, "Using