This turns out to be pretty easy.  You might also want to read Implementing Harmonic Mean in MySQL.

Why bother blogging something this simple?  Because I couldn’t find one pre-made, and that means it’s time to bring my mighty google rank of like negative two to bear to fix the problem.

CREATE TABLE example(val integer);
INSERT INTO example VALUES(1),(2),(4),(8),(16);
SELECT exp(avg(ln(val))) as gmean from example;

That’s it.  You should see output like this:

mysql> CREATE TABLE example(val integer);
Query OK, 0 rows affected (0.09 sec)

mysql> INSERT INTO example VALUES(1),(2),(4),(8),(16);
Query OK, 5 rows affected (0.01 sec)
Records: 5  Duplicates: 0  Warnings: 0

mysql> SELECT exp(avg(ln(val))) as gmean from example;
+- - - -+
| gmean |
+- - - -+
|     4 |
+- - - -+
1 row in set (0.00 sec)

Still haven’t figured out how to do central moments, skewness or kurtosis.

This turns out to be pretty easy.  You might also want to read Implementing Geometric Mean in MySQL.

Why bother blogging something this simple?  Because I couldn’t find one pre-made, and that means it’s time to bring my mighty google rank of like negative two to bear to fix the problem.

CREATE TABLE example(val integer);
INSERT INTO example VALUES(1),(2),(4),(8),(16);
SELECT count(val) / sum(1/val) as hmean from example;

That’s it.  You should see output like this:

mysql> CREATE TABLE example(val integer);
Query OK, 0 rows affected (0.09 sec)

mysql> INSERT INTO example VALUES(1),(2),(4),(8),(16);
Query OK, 5 rows affected (0.01 sec)
Records: 5  Duplicates: 0  Warnings: 0

mysql> SELECT count(val)/sum(1/val) as hmean from example;
+- - - - +
| hmean  |
+- - - - +
| 2.5806 |
+- - - - +
1 row in set (0.00 sec)

Still haven’t figured out how to do central moments, skewness or kurtosis.