LN(X)
Returns the natural logarithm of X; that is, the base-e logarithm of X.
If X is less than or equal to 0, or NULL
, then NULL is returned.
The inverse of this function is EXP().
SELECT LN(2);
+-------------------+
| LN(2) |
+-------------------+
| 0.693147180559945 |
+-------------------+
SELECT LN(-2);
+--------+
| LN(-2) |
+--------+
| NULL |
+--------+