#author("2020-05-20T18:06:48+09:00","default:ryuichi","ryuichi")
* 標準偏差 - stddev_pop stddev_samp [#h1619375]
** 前提 [#v7aa798b]
CREATE TABLE t6 (id int, n int);
INSERT INTO t6 VALUES (1, 90), (2, 80), (3, 40), (4,60), (5, 90)
SELECT * FROM t6;
id | n
----+----
1 | 90
2 | 80
3 | 40
4 | 60
5 | 90
** stddev_pop() stddev_samp() [#s8b4607c]
SELECT AVG(n), stddev_pop(n) FROM t6;
avg | stddev_pop
---------------------+---------------------
72.0000000000000000 | 19.3907194296653161
** 参考 [#d26a45b1]
https://qiita.com/ironsand/items/a614fb9fc39cf89c2dcf