The FLOAT data type is an alias for a REAL or DOUBLE PRECISION data type, depending on the precision you specify.
FLOAT [ (precision) ]
The default precision for FLOAT is 53 and is equivalent to DOUBLE PRECISION. A precision of 23 or less makes FLOAT equivalent to REAL. A precision of 24 or greater makes FLOAT equivalent to DOUBLE PRECISION. If you specify a precision of 0, you get an error. If you specify a negative precision, you get a syntax error.
REAL or DOUBLE
If you are using a precision of 24 or greater, the limits of FLOAT are similar to the limits of DOUBLE.
If you are using a precision of 23 or less, the limits of FLOAT are similar to the limits of REAL.