In MySQL, the LOG10() function returns the base-10 logarithm of a specified value.

You provide the specified value as an argument when calling the function.

Syntax

This syntax goes like this:

LOG10(X)

Where X is the value for which you want the base-10 logarithm returned.

If X is less than or equal to 0.0E0, the function returns NULL and a warning is generated.

Example 1 – Basic Usage

Here’s a basic example to demonstrate how this function works.

SELECT LOG10(10);

Result:

+-----------+
| LOG10(10) |
+-----------+
|         1 |
+-----------+

And here’s another example using various values.

SELECT 
  LOG10(100),
  LOG10(1000),
  LOG10(3000),
  LOG10(10000);

Result:

+------------+-------------+--------------------+--------------+
| LOG10(100) | LOG10(1000) | LOG10(3000)        | LOG10(10000) |
+------------+-------------+--------------------+--------------+
|          2 |           3 | 3.4771212547196626 |            4 |
+------------+-------------+--------------------+--------------+

Example 2 – Negative Value

Here’s an example of passing in a negative value.

SELECT LOG10(-4);

Result:

+-----------+
| LOG10(-4) |
+-----------+
|      NULL |
+-----------+
1 row in set, 1 warning (0.00 sec)

This example returns a NULL value (and a warning) because the argument provided is less than 0.0E0.

Example 3 – Zero

Here’s an example of passing in zero as the argument (we get the same result as the previous example).

SELECT LOG10(0);

Result:

+----------+
| LOG10(0) |
+----------+
|     NULL |
+----------+
1 row in set, 1 warning (0.00 sec)

Example 4 – Expressions

You can also pass in expressions like this:

SELECT LOG10(5*2);

Result:

+------------+
| LOG10(5*2) |
+------------+
|          1 |
+------------+

LOG()

There’s also the LOG() function (and its synonym LN()), which returns the natural logarithm of a number.

In fact, you can use LOG() instead of LOG10() if you prefer. To do this, use 10 as the first argument to the function. Example below.

SELECT 
  LOG(10, 100),
  LOG10(100);

Result:

+--------------+------------+
| LOG(10, 100) | LOG10(100) |
+--------------+------------+
|            2 |          2 |
+--------------+------------+

LOG2()

MySQL also has the LOG2() function that returns the base-2 logarithm of a value.