The FLOAT data type holds a 64-bit, base 2, fraction and exponent approximation to a real number. This gives a range of values between +-1.7E–308 and +- 1.7E+308.
Float literals consist of an unquoted string of digits and either a decimal point (for example 123.4) or an exponent (for example 123e4) or both (for example 123.4e5) . They are of type FLOAT if they are small enough to be represented as floats. Otherwise they are of type DECIMAL