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doris/docs/documentation/cn/sql-reference/sql-functions/aggregate-functions/stddev.md
2019-07-11 16:45:45 +08:00

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STDDEV,STDDEV_POP

Syntax

STDDEV(expr)

Description

返回expr表达式的标准差

Examples

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 |
+-------------------------+