oracle+110个常用函数

30 Tobias 24-7月 -97 2800 4650.0896 30 Baida 24-12月-97 2900 4035.26125 30 Himuro 15-11月-98 2600 3649.2465 30 Colmenares 10-8月 -99 2500 3362.58829 60 Hunold 03-1月 -90 9000

60 Ernst 21-5月 -91 6000 2121.32034 60 Austin 25-6月 -97 4800 2163.33077 60 Pataballa 05-2月 -98 4800 1982.42276 60 Lorentz 07-2月 -99 4200 1925.61678

96。SUM

功能描述：该函数计算组中表达式的累积和。 SAMPLE：下例计算同一经理下员工的薪水累积值 SELECT manager_id, last_name, salary,

SUM (salary) OVER (PARTITION BY manager_id ORDER BY salary RANGE UNBOUNDED PRECEDING) l_csum FROM employees

WHERE manager_id in (101,103,108); MANAGER_ID LAST_NAME SALARY L_CSUM ---------- ------------------------- ---------- ---------- 101 Whalen 4400 4400 101 Mavris 6500 10900 101 Baer 10000 20900 101 Greenberg 12000 44900 101 Higgins 12000 44900 103 Lorentz 4200 4200 103 Austin 4800 13800 103 Pataballa 4800 13800 103 Ernst 6000 19800 108 Popp 6900 6900 108 Sciarra 7700 14600 108 Urman 7800 22400 108 Chen 8200 30600 108 Faviet 9000 39600 97。VAR_POP

功能描述：（Variance Population）该函数返回非空集合的总体变量（忽略null），VAR_POP进行如下计算：

(SUM(expr2) - SUM(expr)2 / COUNT(expr)) / COUNT(expr)

SAMPLE：下例计算1998年每月销售的累积总体和样本变量（本例在SH用户下运行） SELECT t.calendar_month_desc, VAR_POP(SUM(s.amount_sold))

OVER (ORDER BY t.calendar_month_desc) \ VAR_SAMP(SUM(s.amount_sold))

OVER (ORDER BY t.calendar_month_desc) \

FROM sales s, times t

WHERE s.time_id = t.time_id AND t.calendar_year = 1998 GROUP BY t.calendar_month_desc; CALENDAR Var_Pop Var_Samp -------- ---------- ---------- 1998-01 0

1998-02 6.1321E+11 1.2264E+12 1998-03 4.7058E+11 7.0587E+11 1998-04 4.6929E+11 6.2572E+11 1998-05 1.5524E+12 1.9405E+12 1998-06 2.3711E+12 2.8453E+12 1998-07 3.7464E+12 4.3708E+12 1998-08 3.7852E+12 4.3260E+12 1998-09 3.5753E+12 4.0222E+12 1998-10 3.4343E+12 3.8159E+12 1998-11 3.4245E+12 3.7669E+12 1998-12 4.8937E+12 5.3386E+12 ? 98。VAR_SAMP

功能描述：（Variance Sample）该函数返回非空集合的样本变量（忽略null），VAR_POP进行如下计算： (SUM(expr*expr)-SUM(expr)*SUM(expr)/COUNT(expr))/(COUNT(expr)-1) SAMPLE：下例计算1998年每月销售的累积总体和样本变量 SELECT t.calendar_month_desc, VAR_POP(SUM(s.amount_sold))

OVER (ORDER BY t.calendar_month_desc) \ VAR_SAMP(SUM(s.amount_sold))

OVER (ORDER BY t.calendar_month_desc) \ FROM sales s, times t

WHERE s.time_id = t.time_id AND t.calendar_year = 1998 GROUP BY t.calendar_month_desc; CALENDAR Var_Pop Var_Samp -------- ---------- ---------- 1998-01 0

1998-02 6.1321E+11 1.2264E+12 1998-03 4.7058E+11 7.0587E+11 1998-04 4.6929E+11 6.2572E+11 1998-05 1.5524E+12 1.9405E+12 1998-06 2.3711E+12 2.8453E+12 1998-07 3.7464E+12 4.3708E+12 1998-08 3.7852E+12 4.3260E+12 1998-09 3.5753E+12 4.0222E+12 1998-10 3.4343E+12 3.8159E+12 1998-11 3.4245E+12 3.7669E+12 1998-12 4.8937E+12 5.3386E+12 99。VARIANCE

功能描述：该函数返回表达式的变量，Oracle计算该变量如下： 如果表达式中行数为1，则返回0

如果表达式中行数大于1，则返回VAR_SAMP

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

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

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

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