STDDEV,STDDEV_POP
description
Syntax
STDDEV(expr)
返回expr表达式的标准差
example
MySQL > select stddev(scan_rows) from log_statis group by datetime;
+---------------------+
| stddev(`scan_rows`) |
+---------------------+
| 2.3736656687790934 |
+---------------------+
MySQL > select stddev_pop(scan_rows) from log_statis group by datetime;
+-------------------------+
| stddev_pop(`scan_rows`) |
+-------------------------+
| 2.3722760595994914 |
+-------------------------+keywords
STDDEV,STDDEV_POP,POP