MySQL STD()函数

STD(expression)

STDDEV(expression)

STD()函数用于返回表达式的标准差。这是相当于采取的方差的表达的VARIANCE()。下面的示例计算价格的标准差列在我们的CARS：

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