LOG function
Returns logarithm of a number.
If you're using this function to calculate the base 10 logarithm, you can also use DLOG10 function.
Syntax
LOG([base, ]argument)
Parameters
 base

(Optional) The base of the logarithm function. This number must be positive and can't equal
1
. If this parameter is omitted, Amazon Redshift computes the base 10 logarithm of the argument.  argument

The argument of the logarithm function. This number must be positive. If the argument value is
1
, the function returns0
.
Return type
The LOG function returns a DOUBLE PRECISION
number.
Examples
To find the base 2 logarithm of 100, use the following example.
SELECT LOG(2, 100);
++  log  ++  6.643856189774725  ++
To find the base 10 logarithm of 100, use the following example. Note that if you omit the base parameter, Amazon Redshift assumes a base of 10.
SELECT LOG(100);
++  log  ++  2  ++