FLOAT[(M,D)] [UNSIGNED] [ZEROFILL] : FLOAT « Data Types « MySQL Tutorial

A small (single-precision) floating-point number.

Allowable values are -3.402823466E+38 to -1.175494351E-38, 0, and 1.175494351E-38 to 3.402823466E+38.

M is the total number of digits.

D is the number of digits following the decimal point.

If M and D are omitted, values are stored to the limits allowed by the hardware.

A single-precision floating-point number is accurate to approximately 7 decimal places.

10.11.3.For floating-point values, results are inexact: