Categories:

Numeric Functions (Logarithmic)

LOG

Returns the logarithm of a numeric expression.

See also:

natural log (ln)

Syntax

LOG(<base>, <expr>)

Arguments

base

The “base” to use (e.g. 10 for base 10 arithmetic).

This can be of any numeric data type (INTEGER, fixed-point, or floating point).

base should be greater than 0.

base should not be exactly 1.0.

expr

The value for which you want to know the log.

This can be of any numeric data type (INTEGER, fixed-point, or floating point).

expr should be greater than 0.

Returns

Always returns a floating point number, even if one or more of the input expressions are of type integer or fixed-point.

Usage Notes

  • If base is 1 or less than or equal to 0, an error is returned.

  • If expr is less than or equal to 0, an error is returned.

Examples

SELECT x, y, log(x, y) FROM tab;

--------+--------+-------------+
   X    |   Y    |  LOG(X, Y)  |
--------+--------+-------------+
 2      | 0.5    | -1          |
 2      | 1      | 0           |
 2      | 8      | 3           |
 2      | 16     | 4           |
 10     | 10     | 1           |
 10     | 20     | 1.301029996 |
 10     | [NULL] | [NULL]      |
 [NULL] | 10     | [NULL]      |
 [NULL] | [NULL] | [NULL]      |
--------+--------+-------------+