How can I Calcualte the geometric mean in oracle 10g

Question

dear all
plz I need a function to calculate the geometric mean
I uses oracle 10g
thanks in advance

Answer 1

Hi,
Solomon Yakobson wrote:
select  power(10,sum(log(10,val)) / count(*))
from  value_table
I'm sure you meant count *(val)*, not count (*).
You can also use AVG instead of SUM and COUNT.
There's nothing specail about the number 10; any number greater than 1 will do; just be sure to use the same number in both POWER and LOG. If you used e, that would be equivalent to using EXP and LN instead of POWER and LOG, so why not use EXP and LN in the first place?
SELECT       job
,       power(10,sum(log(10,sal)) / count(*))     AS gm1
,       POWER ( 2
          , AVG (LOG (2, sal))
          )                    AS gm2
,       EXP (AVG (LN (sal)))               AS gm3
FROM       scott.emp
GROUP BY  job
ORDER BY  job
;Output:
JOB              GM1        GM2        GM3
ANALYST         3000       3000       3000
CLERK     1021.02742 1021.02742 1021.02742
MANAGER    2748.9445  2748.9445  2748.9445
PRESIDENT       5000       5000       5000
SALESMAN  1391.57884 1391.57884 1391.57884