Exponential and Logarithmic Functions:
|--+-EXP--(--float_expression--)---+----------------------------|
+-LOGN--(--float_expression--)--+
'-LOG10--(--float_expression--)-'
Exponential and logarithmic functions take at least one argument and return a FLOAT data type.
| Element | Description | Restrictions | Syntax |
|---|---|---|---|
| float_expression | An argument to the EXP, LOGN, or LOG10 functions. For the meaning of float_expression in these functions, see the individual heading for each function on the pages that follow. | The domain is the set of real numbers, and the range is the set of positive real numbers | Expression, p. Expression |
The EXP function returns the exponent of a numeric expression. The following example returns the exponent of 3 for each row of the angles table:
SELECT EXP(3) FROM angles
For this function, the base is always e, the base of natural logarithms, as the following example shows:
e=exp(1)=2.718281828459
When you want to use the base of natural logarithms as the base value, use the EXP function. If you want to specify a particular value to raise to a specific power, see the POW Function.
The LOG10 function returns the log of a value to base 10. The following example returns the log base 10 of distance for each row of the travel table:
SELECT LOG10(distance) + 1 digits FROM travel
The LOG10 function returns the log of a value to base 10. The following example returns the log base 10 of distance for each row of the travel table:
SELECT LOG10(distance) + 1 digits FROM travel
The LOGN function returns the natural logarithm of a numeric argument. This value is the inverse of the exponential value. The following query returns the natural log of population for each row of the history table:
SELECT LOGN(population) FROM history WHERE country='US' ORDER BY dateEnterprise Edition Home | Express Edition Home | [ Top of Page | Previous Page | Next Page | Contents | Index ]