DOUBLE[(M,D)] [UNSIGNED] [ZEROFILL]
A normal-size (double-precision) floating-point number. Permissible
values are -1.7976931348623157E+308 to -2.2250738585072014E-308, 0, and
2.2250738585072014E-308 to 1.7976931348623157E+308. These are the
theoretical limits, based on the IEEE standard. The actual range might
be slightly smaller depending on your hardware or operating system.
M is the total number of digits and D is the number of digits following
the decimal point. If M and D are omitted, values are stored to the
limits permitted by the hardware. A double-precision floating-point
number is accurate to approximately 15 decimal places.
DOUBLE(M,D) is a nonstandard MySQL extension. As of MySQL 8.0.17, this
syntax is deprecated and support for it will be removed in a future
UNSIGNED, if specified, disallows negative values. As of MySQL 8.0.17,
the UNSIGNED attribute is deprecated for columns of type DOUBLE (and
any synonyms) and support for it will be removed in a future MySQL
version. Consider using a simple CHECK constraint instead for such