SAMPLE：下例返回部门30按雇佣日期排序的薪水值的累积变化 SELECT last_name, salary, VARIANCE(salary) OVER (ORDER BY hire_date) \ FROM employees
WHERE department_id = 30; LAST_NAME SALARY Variance
------------------------- ---------- ----------
Raphaely 11000 0 Khoo 3100 31205000 Tobias 2800 21623333.3 Baida 2900 16283333.3 Himuro 2600 13317000 Colmenares 2500 11307000
100、RANK根据ORDER BY子句中表达式的值，从查询返回的每一行，计算它们与其它行的相对位置
功能描述：根据ORDER BY子句中表达式的值，从查询返回的每一行，计算它们与其它行的相对位置。组内的数据按ORDER BY子句排序，
然后给每一行赋一个号，从而形成一个序列，该序列从1开始，往后累加。每次ORDER BY表达式的值
发生变化时，该序列也随之增加。
有同样值的行得到同样的数字序号（认为null时相等的）。然而，如果两行的确得到同样的排序，则序数将随后跳跃。若两行序数为1，
则没有序数2，序列将给组中的下一行分配值3，DENSE_RANK则没有任何跳跃。
SAMPLE：下例中计算每个员工按部门分区再按薪水排序，依次出现的序列号（注意与DENSE_RANK函
数的区别）
SELECT d.department_id , e.last_name, e.salary, RANK()
OVER (PARTITION BY e.department_id ORDER BY e.salary) as drank FROM employees e, departments d WHERE e.department_id = d.department_id AND d.department_id IN ('60', '90');
DEPARTMENT_ID LAST_NAME SALARY DRANK
------------- ------------------------- ---------- ----------
60 Lorentz 4200 1 60 Austin 4800 2 60 Pataballa 4800 2 60 Ernst 6000 4 60 Hunold 9000 5 90 Kochhar 17000 1 90 De Haan 17000 1 90 King 24000 3
101、RATIO_TO_REPORT 计算expression/(sum(expression))的值，它给出相对于总数的百分比
功能描述：该函数计算expression/(sum(expression))的值，它给出相对于总数的百分比，即当前行对sum(expression)的贡献。
SAMPLE：下例计算每个员工的工资占该类员工总工资的百分比
SELECT last_name, salary, RATIO_TO_REPORT(salary) OVER () AS rr FROM employees
WHERE job_id = 'PU_CLERK'; LAST_NAME SALARY RR
------------------------- ---------- ----------
Khoo 3100 .223021583 Baida 2900 .208633094 Tobias 2800 .201438849 Himuro 2600 .18705036 Colmenares 2500 .179856115
102、REGR_ (Linear Regression) Functions 线性回归函数适合最小二乘法回归线 功能描述：这些线性回归函数适合最小二乘法回归线，有9个不同的回归函数可使用。 REGR_SLOPE：返回斜率，等于COVAR_POP(expr1, expr2) / VAR_POP(expr2) REGR_INTERCEPT：返回回归线的y截距，等于
AVG(expr1) - REGR_SLOPE(expr1, expr2) * AVG(expr2) REGR_COUNT：返回用于填充回归线的非空数字对的数目 REGR_R2：返回回归线的决定系数，计算式为： If VAR_POP(expr2) = 0 then return NULL
If VAR_POP(expr1) = 0 and VAR_POP(expr2) != 0 then return 1 If VAR_POP(expr1) > 0 and VAR_POP(expr2 != 0 then return POWER(CORR(expr1,expr),2) REGR_AVGX：计算回归线的自变量(expr2)的平均值，去掉了空对(expr1, expr2)后，等于AVG(expr2)
REGR_AVGY：计算回归线的应变量(expr1)的平均值，去掉了空对(expr1, expr2)后，等于AVG(expr1)
REGR_SXX： 返回值等于REGR_COUNT(expr1, expr2) * VAR_POP(expr2) REGR_SYY： 返回值等于REGR_COUNT(expr1, expr2) * VAR_POP(expr1)
REGR_SXY: 返回值等于REGR_COUNT(expr1, expr2) * COVAR_POP(expr1, expr2) （下面的例子都是在SH用户下完成的）
SAMPLE 1：下例计算1998年最后三个星期中两种产品（260和270）在周末的销售量中已开发票数量和总数量的累积斜率和回归线的截距
SELECT t.fiscal_month_number \ REGR_SLOPE(s.amount_sold, s.quantity_sold)
OVER (ORDER BY t.fiscal_month_desc, t.day_number_in_month) AS CUM_SLOPE, REGR_INTERCEPT(s.amount_sold, s.quantity_sold)
OVER (ORDER BY t.fiscal_month_desc, t.day_number_in_month) AS CUM_ICPT FROM sales s, times t WHERE s.time_id = t.time_id AND s.prod_id IN (270, 260) AND t.fiscal_year=1998
AND t.fiscal_week_number IN (50, 51, 52) AND t.day_number_in_week IN (6,7)
ORDER BY t.fiscal_month_desc, t.day_number_in_month;
Month Day CUM_SLOPE CUM_ICPT ---------- ---------- ---------- ---------- 12 12 -68 1872 12 12 -68 1872
12 13 -20.244898 1254.36735 12 13 -20.244898 1254.36735 12 19 -18.826087 1287 12 20 62.4561404 125.28655 12 20 62.4561404 125.28655 12 20 62.4561404 125.28655 12 20 62.4561404 125.28655 12 26 67.2658228 58.9712313 12 26 67.2658228 58.9712313 12 27 37.5245541 284.958221 12 27 37.5245541 284.958221 12 27 37.5245541 284.958221
SAMPLE 2：下例计算1998年4月每天的累积交易数量 SELECT UNIQUE t.day_number_in_month, REGR_COUNT(s.amount_sold, s.quantity_sold) OVER (PARTITION BY t.fiscal_month_number ORDER BY t.day_number_in_month) \
FROM sales s, times t WHERE s.time_id = t.time_id
AND t.fiscal_year = 1998 AND t.fiscal_month_number = 4; DAY_NUMBER_IN_MONTH Regr_Count ------------------- ---------- 1 825 2 1650 3 2475 4 3300 .
26 21450 30 22200
SAMPLE 3：下例计算1998年每月销售量中已开发票数量和总数量的累积回归线决定系数 SELECT t.fiscal_month_number,
REGR_R2(SUM(s.amount_sold), SUM(s.quantity_sold)) OVER (ORDER BY t.fiscal_month_number) \ FROM sales s, times t WHERE s.time_id = t.time_id AND t.fiscal_year = 1998
GROUP BY t.fiscal_month_number ORDER BY t.fiscal_month_number; FISCAL_MONTH_NUMBER Regr_R2 ------------------- ----------
1 2 1
3 .927372984 4 .807019972 5 .932745567 6 .94682861 7 .965342011 8 .955768075 9 .959542618 10 .938618575 11 .880931415 12 .882769189
SAMPLE 4：下例计算1998年12月最后两周产品260的销售量中已开发票数量和总数量的累积平均值
SELECT t.day_number_in_month,
REGR_AVGY(s.amount_sold, s.quantity_sold)
OVER (ORDER BY t.fiscal_month_desc, t.day_number_in_month) \
REGR_AVGX(s.amount_sold, s.quantity_sold)
OVER (ORDER BY t.fiscal_month_desc, t.day_number_in_month) \
FROM sales s, times t WHERE s.time_id = t.time_id AND s.prod_id = 260
AND t.fiscal_month_desc = '1998-12' AND t.fiscal_week_number IN (51, 52) ORDER BY t.day_number_in_month;
DAY_NUMBER_IN_MONTH Regr_AvgY Regr_AvgX ------------------- ---------- ---------- 14 882 24.5 14 882 24.5 15 801 22.25 15 801 22.25 16 777.6 21.6
18 642.857143 17.8571429 18 642.857143 17.8571429 20 589.5 16.375 21 544 15.1111111
22 592.363636 16.4545455 22 592.363636 16.4545455 24 553.846154 15.3846154 24 553.846154 15.3846154 26 522 14.5
27 578.4 16.0666667
SAMPLE 5：下例计算产品260和270在1998年2月周末销售量中已开发票数量和总数量的累积REGR_SXY, REGR_SXX, and REGR_SYY统计值 SELECT t.day_number_in_month,
REGR_SXY(s.amount_sold, s.quantity_sold)
OVER (ORDER BY t.fiscal_year, t.fiscal_month_desc) \ REGR_SYY(s.amount_sold, s.quantity_sold)
OVER (ORDER BY t.fiscal_year, t.fiscal_month_desc) \ REGR_SXX(s.amount_sold, s.quantity_sold)
OVER (ORDER BY t.fiscal_year, t.fiscal_month_desc) \ FROM sales s, times t WHERE s.time_id = t.time_id AND prod_id IN (270, 260)
AND t.fiscal_month_desc = '1998-02' AND t.day_number_in_week IN (6,7) ORDER BY t.day_number_in_month;
DAY_NUMBER_IN_MONTH Regr_sxy Regr_syy Regr_sxx ------------------- ---------- ---------- ---------- 1 18870.4 2116198.4 258.4 1 18870.4 2116198.4 258.4 1 18870.4 2116198.4 258.4 1 18870.4 2116198.4 258.4 7 18870.4 2116198.4 258.4 8 18870.4 2116198.4 258.4 14 18870.4 2116198.4 258.4 15 18870.4 2116198.4 258.4 21 18870.4 2116198.4 258.4 22 18870.4 2116198.4 258.4
103、ROW_NUMBER 返回有序组中一行的偏移量，从而可用于按特定标准排序的行号
功能描述：返回有序组中一行的偏移量，从而可用于按特定标准排序的行号。 SAMPLE：下例返回每个员工再在每个部门中按员工号排序后的顺序号 SELECT department_id, last_name, employee_id, ROW_NUMBER() OVER (PARTITION BY department_id ORDER BY employee_id) AS emp_id FROM employees
WHERE department_id < 50;
DEPARTMENT_ID LAST_NAME EMPLOYEE_ID EMP_ID ------------- ------------------------- ----------- ---------- 10 Whalen 200 1 20 Hartstein 201 1 20 Fay 202 2 30 Raphaely 114 1 30 Khoo 115 2 30 Baida 116 3
30 Tobias 117 4