HistoryIn SQL, a number -- i.e.: any signed, or unsigned, combination of the digits 0 to 9 -- is either an exact numeric value or an approximate numeric value. A numeric value may be a <literal>, the value of a parameter or a host language variable or the result of any expression or argument (including a possibly qualified <Column name>) that evaluates to a number.
Exact numeric values have a precision and a scale. The precision is a positive
integer that determines the number of significant digits in the radix. The
scale is a non-negative integer that specifies the number of digits to the
right of the value's decimal point. Exact numeric values are stored in one of
the four exact numeric <data type>s: INTEGER,
SMALLINT, NUMERIC or DECIMAL.
Approximate numeric values, or floating point numbers, have two parts: a signed
decimal number (the mantissa) and a signed integer (the exponent). The
exponent specifies the magnitude of the mantissa, so the value of such a number
is the mantissa raised to the power of the exponent. Approximate numeric values
also have a precision: a positive integer that specifies the number of
significant bits in the mantissa. Approximate numeric values are stored in one
of the three approximate numeric <data type>s: FLOAT,
REAL or DOUBLE PRECISION.
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