/* Formatted on 5/24/2012 4:15:58 PM (QP5 v5.149.1003.31008) */
SELECT deptno,
ename, --st_name || ' ' || last_name employee_name,
hiredate,
sal,
STDDEV (sal) OVER (PARTITION BY deptno ORDER BY hiredate) AS "STDDEV", --標准差
STDDEV_SAMP (sal) OVER (PARTITION BY deptno ORDER BY hiredate)
AS "STDDEV_SAMP", --樣本標准差
VAR_POP (sal) OVER (PARTITION BY deptno ORDER BY hiredate) 說明:VAR_POP 為函數, sal為要求的數據列, 以‘deptno’為分組的根據,即滿足這個條件下才進行方差的操作,最后根據‘hiredate’進行排序。
AS "VAR_POP", --方差
VAR_SAMP (sal) OVER (PARTITION BY deptno ORDER BY hiredate)
AS "VAR_SAMP" --樣本方差
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", --標准差
STDDEV_SAMP (sal)
AS "STDDEV_SAMP", --樣本標准差
VAR_POP (sal)
AS "VAR_POP", --方差
VAR_SAMP (sal)
AS "VAR_SAMP" --樣本方差
FROM scott.emp
group by deptno