MySQL floating-point type and fixed-point number type

In MySQL, floating-point numbers and fixed-points are used to represent decimals, and floating-point numbers include single-precision floating-point types (float) and double-precision floating-point types (double), with a fixed-point number of only decimal types. Both floating-point and fixed-point types can be represented by (M, N), where M is precision, which represents the total number of digits, and N is the scale that represents the number of decimal places.

(1) floating point and fixed point number: Floating point is the decimal point in the decimal position is not fixed, the point number refers to the decimal point in the position of the decimal is fixed
(2) Single-precision and double-precision: single-precision with 4 bytes to store, double-precision with 8 bytes to store, because of different storage bits, they can represent a different range of values, that is, the number of digits can be accurately represented is different.

Type name	Description	Storage requirements	Signed Value Range	Unsigned range of values
FLOAT	Single-precision floating-point number	4 bytes	-3.4028 ~-1.1754	0 and 1.1754 ~ 3.4028
DOUBLE	Double-precision floating-point number	8 bytes	-1.7976 ~-2.2250	0 and 2.2250 ~ 1.7976
DECIMAL	Compressed "strict" fixed-point number	m+2 bytes	Not fixed	Not fixed

MySQL floating-point type and fixed-point number type