使用oracle来计算方差及标准差

          AS "VAR_POP",                                                   --方差
       VAR_SAMP (sal) OVER (PARTITION BY deptno ORDER BY hiredate)
          AS "VAR_SAMP"                                                 --样本方差
  FROM scott.emp
 WHERE deptno IN (20);
 
 /* Formatted on 5/24/2012 4:15:58 PM (QP5 v5.149.1003.31008) */
SELECT deptno,
       STDDEV (sal)  AS "STDDEV", --标准差
       STDDEV_SAMP (sal)
          AS "STDDEV_SAMP",                                            --样本标准差
       VAR_POP (sal)
          AS "VAR_POP",                                                   --方差
       VAR_SAMP (sal)
          AS "VAR_SAMP"                                                 --样本方差
  FROM scott.emp
group  by deptno

使用oracle来计算方差及标准差

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