STD()函數(shù)是用于返回表達(dá)的標(biāo)準(zhǔn)偏差。 這相當(dāng)于服用表達(dá)的VARIANCE()的平方根。下面的例子計(jì)算CARS表列價(jià)格的標(biāo)準(zhǔn)差:
SQL>SELECT STD(PRICE) STD_DEVIATION FROM CARS; +---------------------------------------------------------+ | STD_DEVIATION | +---------------------------------------------------------+ | 7650.2146 | +---------------------------------------------------------+ 1 row in set (0.00 sec)