STD(expression)

STDDEV(expression)

STD()函数是用于返回表达的标准偏差。 这相当于服用表达的VARIANCE()的平方根。下面的例子计算CARS表列价格的标准差：

SQL>SELECT STD(PRICE) STD_DEVIATION FROM CARS;
+---------------------------------------------------------+
| STD_DEVIATION                                           |
+---------------------------------------------------------+
| 7650.2146                                               |
+---------------------------------------------------------+
1 row in set (0.00 sec)