   DOUBLE[(M,B)] [UNSIGNED] [ZEROFILL]

A normal-size (double-precision) floating-point number. Allowable values are
-1.7976931348623157E+308 to -2.2250738585072014E-308,
0, and 2.2250738585072014E-308 to 1.7976931348623157E+308.
If UNSIGNED is specified, negative values are disallowed. M is the
display width and B is the number of bits of precision. DOUBLE
without arguments or FLOAT(p) (where p is in the range from
25 to 53) stands for a double-precision floating-point number. A
single-precision floating-point number is accurate to approximately 7 decimal
places; a double-precision floating-point number is accurate to approximately 15
decimal places.

   DOUBLE PRECISION[(M,D)] [UNSIGNED] [ZEROFILL]
   REAL[(M,D)] [UNSIGNED] [ZEROFILL]

These are synonyms for DOUBLE.
Exception: If the server SQL mode includes the REAL_AS_FLOAT option,
REAL is a synonym for FLOAT rather than DOUBLE.
