Syntax
LN(X)
Purpose
You can call this function to return the natural logarithm of X, which is the base-e logarithm of X. If X is less than or equal to 0, the function returns NULL and reports the alert Invalid argument for logarithm.
This function is a synonym of the LOG(X) function.
Examples
obclient> SELECT LN(-10), LN(0), LN(10), LN(-3.14), LN(3.14);
+---------+-------+-------------------+-----------+-------------------+
LN(-10) LN(0) LN(10) LN(-3.14) LN(3.14)
+---------+-------+-------------------+-----------+-------------------+
NULL NULL 2.302585092994046 NULL 1.144222799920162
+---------+-------+-------------------+-----------+-------------------+
1 row in set, 3 warnings (0.00 sec)
obclient> SHOW WARNINGS;
+---------+------+--------------------------------+
Level Code Message
+---------+------+--------------------------------+
Warning 3020 Invalid argument for logarithm
Warning 3020 Invalid argument for logarithm
Warning 3020 Invalid argument for logarithm
+---------+------+--------------------------------+
3 rows in set (0.00 sec)
