聚合函数就是基于多行数据返回一行结果，下面就是Oracle提供的一些列聚合函数：
AVG
COLLECT
CORR
CORR_*
COUNT
COVAR_POP
COVAR_SAMP
CUME_DIST
DENSE_RANK
FIRST
GROUP_ID
GROUPING
GROUPING_ID
LAST
LISTAGG
MAX
MEDIAN
MIN
PERCENT_RANK
PERCENTILE_CONT
PERCENTILE_DISC
RANK
REGR_(Linear Regression) Functions
STATS_BINOMIAL_TEST
STATS_CROSSTAB
STATS_F_TEST
STATS_KS_TEST
STATS_MODE
STATS_MW_TEST
STATS_ONE_WAY_ANOVA
STATS_T_TEST_*
STATS_WSR_TEST
STDDEV
STDDEV_POP
STDDEV_SAMP
SUM
SYS_XMLAGG
VAR_ POP
VAR_ SAMP
VARI ANCE
XMLAGG
1、AVG( distinct|all,expr,over(analytic_clause) ) 求平均值
SELECT deptno,AVG(sal) "Average"
From emp
Group By Deptno
order by deptno;
Select Mgr, Ename, Hiredate, Sal,
AVG(sal) OVER (PARTITION BY mgr ORDER BYhiredate ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING) AS c_mavg
From Emp
ORDER BY Mgr, Hiredate, Sal;
2、COLLECT(distinct|unique,column,orderby expr)
将结果转换为一个嵌套表
CREATE TYPE phone_book_t AS TABLE OFphone_list_typ;
/
SELECT CAST(COLLECT(phone_numbers) ASphone_book_t) Phone_Book
FROM customers
ORDER BY phone_book;
3、CORR( expr1,expr2,over(analytic_clause) ) 返回一对表达式的相关系数[返回一个-1~1的数，相关系数给出了关联的强度，0表示不相关]
Select Deptno,CORR(empno,mgr) a1
From Emp
Group By Deptno;
SELECT empno, job,
TO_CHAR((SYSDATE - hiredate) YEAR TO MONTH )"Yrs-Mns", sal,
CORR(SYSDATE-hiredate, sal)
Over(Partition By Job) As"Correlation"
FROM emp
4、CORR_K(expr1,expr2,
COEFFICIENT|ONE_SIDED_SIG|ONE_SIDED_SIG_POS|ONE_SIDED_SIG_NEG|TWO_SIDED_SIG));
CORR_S(expr1,expr2,
COEFFICIENT|ONE_SIDED_SIG|ONE_SIDED_SIG_POS|ONE_SIDED_SIG_NEG|TWO_SIDED_SIG));
COEFFICIENT：相关系数
ONE_SIDED_SIG ：Positive one-tailed significance of the correlation
ONE_SIDED_SIG_POS ：Same as ONE_SIDED_SIG
ONE_SIDED_SIG_NEG ：Negative one-tailed significance of the correlation
TWO_SIDED_SIG ：Two-tailed significanceof the correlation
Select Count(*) Count,
CORR_S(sal, mgr) commission,
CORR_S(sal, Empno) empid
FROM emp;
Select Corr_K(Sal, mgr, 'COEFFICIENT')Coefficient,
Corr_K(Sal, mgr, 'TWO_SIDED_SIG')Two_Sided_P_Value
FROM emp;
5、Count(distinct|all expr) OVER(analytic_clause)
select count(*) a1 from emp;
Select Ename, Sal,
COUNT(*) OVER (ORDER BY sal RANGE BETWEEN 50PRECEDING AND 150 FOLLOWING) AS mov_count
From Emp
ORDER BY sal,ename;
6、COVAR_POP(expr1,expr2)OVER(analytic_clause) 返回一对表达式的协方差[(SUM(expr1 * expr2) - SUM(expr2) * SUM(expr1) / n) / n]
7、COVAR_SAMP(expr1,expr2)OVER(analytic_clause) 返回一对表达式的样本方差[(SUM(expr1 * expr2) - SUM(expr1) * SUM(expr2) / n) / (n-1)]
SELECT job,
COVAR_POP(SYSDATE-hiredate, sal) AS covar_pop,
COVAR_SAMP(SYSDATE-hiredate, sal) AScovar_samp
FROM emp
WHERE 1=1
Group By job
ORDER BY job, covar_pop, covar_samp;
8、CUME_DIST(expr)WITHIN GROUP (ORDER BY expr DESC|ASC NULLS FIRST|LAST)
CUME_DIST() OVER (query_partition_clause order_by_clause)
求累计分布，结果范围(0,1]
Select Cume_Dist(15500, 0.05) Within Group
(Order By Sal, mgr) "Cume-Dist of15500"
From Emp;
SELECT job, ename, sal, CUME_DIST()
Over (Partition By Job Order By Sal) AsCume_Dist
FROM emp
Where 1=1
ORDER BY job, ename, sal, cume_dist;
9、DENSE_RANK(expr)WITHIN GROUP (ORDER BY expr DESC|ASC NULLS FIRST|LAST)
DENSE_RANK() OVER (query_partition_clause order_by_clause)
结果集排序(如果有两个第二名，那么下一个还是第三名)
SELECT DENSE_RANK(15500, 0.05) WITHIN GROUP
(Order By Sal Desc, mgr) "DenseRank"
From Emp;
Select tmp.Dname,tmp.Ename,tmp.Sal,tmp.Drank
From
(
SelectD.Dname, E.Ename, E.Sal, Dense_Rank()
Over(Partition By E.deptno Order By E.Sal) As Drank
FromEmp E, Dept D
WhereE.Deptno = D.Deptno
)Tmp
where 1=1
10、RANK(expr) WITHINGROUP (ORDER BY expr DESC|ASC NULLS FIRST|LAST)
RANK() OVER (query_partition_clause order_by_clause)
结果集排序(如果有两个第二名，那么下一个还是第四名)
SELECT RANK(15500) WITHIN GROUP (Order By SalDesc) "Rank of 15500"
FROM emp;
Select Deptno, Ename, Sal, Mgr,
RANK() OVER (PARTITION BY deptno ORDER BY salDESC, mgr) "Rank"
From emp
Where 1=1
ORDER BY deptno, ename, sal, mgr, "Rank";
11、First
aggregate_function KEEP
(DENSE_RANK FIRST ORDER BY expr DESC|ASCNULLS FIRST|LAST)
OVER (query_partition_clause)
12、LAST
aggregate_function KEEP
(DENSE_RANK LAST ORDER BY expr DESC|ASCNULLS FIRST|LAST)
OVER (query_partition_clause)
Select Deptno,
MIN(sal) KEEP (DENSE_RANK FIRST ORDER BYempno) "Worst",
MAX(sal) KEEP (DENSE_RANK LAST ORDER BY empno)"Best"
From Emp
Group By Deptno
ORDER BY deptno;
Select Deptno,Ename, Sal,
Min(Sal) Keep (Dense_Rank First Order Byename) Over (Partition By deptno) "Worst",
MAX(sal) KEEP (DENSE_RANK LAST ORDER BY ename)OVER (PARTITION BY deptno) "Best"
From Emp
ORDER BY deptno, sal, ename;
13、GROUP_ID() 用于消除GROUP BY子句返回的重复记录。GROUP_ID()不接受任何参数。如果某个特定的分组重复出现n次，那么GROUP_ID()返回从0到n-1之间的一个整数,可以通过 Having GROUP_ID()=0 来消除重复
14、GROUPING(expr) 用于区分常规行与合计(总计)行
GROUPING(expr) 常与 GROUP BY ROLLUP(expr)、GROUP BY CUBE(expr)一起使用
Select deptno,count(empno)a1,GROUP_ID()a2,GROUPING(deptno) a3
From Emp
Group By rollup(deptno)
order by deptno
15、GROUPING_ID(expr) 返回GROUPING位向量的十进制值。GROUPING位向量的计算方法是将按照顺序对每一列调用GROUPING函数的结果组合起来
Select deptno,job,count(empno)a1,GROUP_ID()a2,GROUPING(deptno) a3,GROUPING_ID(deptno,job) a4
From Emp
Group By Rollup(Deptno,Job)
order by deptno,job;
16、LISTAGG(measure_expr, delimiter) WITHIN GROUP (order_by_clause)
OVER (query_partition_clause)字符串聚合(拼接)，这个函数在11G R2中新增，运用很广泛，以前还需要自己写一个拼接的函数
SELECT LISTAGG(ename, '; ') WITHIN GROUP(ORDER BY hiredate, empno) "Emp_list",
MIN(hiredate) "Earliest"
FROM emp
WHERE 1=1;
Select Deptno,
Listagg(ename, '; ') Within Group (Order ByHireDate) "Employees"
FROM emp
Group By deptno
ORDER BY deptno;
在oracle 10G中 可以考虑： WMSYS.WM_CONCAT
17、MAX (DISTINCT|ALL expr) OVER ( analytic_clause ) 返回最大值
18、MIN (DISTINCT|ALL expr) OVER ( analytic_clause ) 返回最小值
Select Deptno,Max(Sal),MIN(sal)
From Emp
group by deptno;
Select Mgr, Ename, Sal,
Max(Sal) Over (Partition By Mgr) As Mgr_Max,
MIN(sal) OVER (PARTITION BY mgr) AS mgr_min
From Emp
ORDER BY mgr, ename, sal;
19、MEDIAN ( expr ) OVER( query_partition_clause ) 返回一组数据的中间值
例如：{1,2,3,4,5} 则返回3，{1,2,3,4}则返回(2+3)/2
with tab as(
Select1 Num From Dual Union All
select3 from dual union all
select20 from dual union all
select12 from dual
)
Select Median(Num) a1 From tab;
SELECT deptno, MEDIAN(sal)
From Emp
Group By Deptno
ORDER BY deptno;
20、PERCENT_RANK ( expr)WITHIN GROUP ( ORDER BY expr DESC|ASC NULLS FIRST|LAST)
PERCENT_RANK ( ) OVER (query_partition_clauseorder_by_clause )
和CUME_DIST（累积分配）函数类似，对于一个组中给定的行来说，在计算那行的序号时，先减1，然后除以n-1（n为组中所有的行数）。该函数总是返回0～1（包括1）之间的数
SELECT PERCENT_RANK(15000,0.05) WITHIN GROUP(ORDER BY sal,mgr) "Percent-Rank"
From emp;
Select Deptno,Ename,Sal,Percent_Rank()Over(Partition By Deptno Order By Sal) Pr
From Emp
order by deptno,sal;
21、PERCENTILE_CONT (expr ) WITHIN GROUP ( ORDER BY expr DESC|ASC)
OVER ( query_partition_clause )
返回一个与输入的分布百分比值相对应的数据值，分布百分比的计算方法同函数PERCENT_RANK()，
如果没有正好对应的数据值，就通过下面算法来得到值：
RN = 1+ (P*(N-1)) 其中P是输入的分布百分比值，N是组内的行数
CRN = CEIL(RN) FRN= FLOOR(RN)
If (CRN =FRN = RN) then the result is
(value of expression from row at RN)
Otherwisethe result is
(CRN - RN) * (value of expression for row at FRN) +
(RN - FRN) * (value of expression for row at CRN)
SELECT deptno,
PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BYsal DESC) "Median cont",
PERCENTILE_DISC(0.5) WITHIN GROUP (ORDER BYsal DESC) "Median disc"
FROM emp
Group By deptno
ORDER BY deptno;
SELECT ename, sal, deptno,
PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BYsal DESC) OVER (PARTITION BY deptno) "Percentile_Cont",
PERCENT_RANK() OVER (PARTITION BY deptno ORDERBY sal DESC) "Percent_Rank"
FROM emp
ORDER BY ename, sal, deptno;
22、PERCENTILE_DISC (expr ) WITHIN GROUP ( ORDER BY expr DESC|ASC)
OVER ( query_partition_clause )
percentile_disc函数在功能上类似于percentile_cont函数，只是percentile_cont函数使用了连续分布模型，而percentile_disc函数使用了离期分布模型。当没有值与指定的percent_rank精确匹配的时候，percentile_cont(0.5)会计算两个离得最近的值的平均值。相反，在升序排列的情况下，percentile_disc函数只取比所传递的参数percent_rank值更大的值。在降序排列的时候，percentile_disc函数只取比所传递的参数percent_rank值更小的值。
Select Ename, Sal, Deptno,
Percentile_Disc(0.5) Within Group (Order BySal Desc) Over (Partition By Deptno) "Percentile_Disc",
CUME_DIST() OVER (PARTITION BY deptno ORDER BYsal DESC) "Cume_Dist"
FROM emp
ORDER BY ename, sal, deptno
23、REGR_ (线性回归) 函数
The linear regression functions are:
■ REGR_SLOPE
■ REGR_INTERCEPT
■ REGR_COUNT
■ REGR_R2
■ REGR_AVGX
■ REGR_AVGY
■ REGR_SXX
■ REGR_SYY
■ REGR_SXY
语法：
fun_name(expr1,expr2) OVER(analytic_clause)
SELECT job, empno ID, sal,
REGR_SLOPE(SYSDATE-hiredate, sal)
OVER (PARTITION BY job) slope,
REGR_INTERCEPT(SYSDATE-hiredate, sal)
Over (Partition By Job) Intcpt,
REGR_R2(SYSDATE-hiredate, sal)
OVER (PARTITION BY job) rsqr,
REGR_COUNT(SYSDATE-hiredate, sal)
OVER (PARTITION BY job) count,
REGR_AVGX(SYSDATE-hiredate, sal)
OVER (PARTITION BY job) avgx,
REGR_AVGY(SYSDATE-hiredate, sal)
OVER (PARTITION BY job) avgy
From Emp
ORDER BY job, empno;
SELECT job,
Regr_Slope(Sysdate-Hiredate, Sal) Slope,
Regr_Intercept(Sysdate-Hiredate, Sal)Intercept
FROM emp
Group By Job
ORDER BY job;
SELECT job,
REGR_COUNT(SYSDATE-hiredate, sal) count
From Emp
Group By Job
ORDER BY job, count;
SELECT job,
Regr_R2(Sysdate-Hiredate, Sal) Regr_R2
FROM emp
Group By Job
ORDER BY job, Regr_R2;
SELECT job,
REGR_AVGY(SYSDATE-hiredate, sal) avgy,
Regr_Avgx(Sysdate-Hiredate, Sal) Avgx
FROM emp
Group By Job
ORDER BY job, avgy, avgx
SELECT job,
REGR_SXY(SYSDATE-hiredate, sal) regr_sxy,
REGR_SXX(SYSDATE-hiredate, sal) regr_sxx,
Regr_Syy(Sysdate-Hiredate, Sal) Regr_Syy
FROM emp
Group By Job
ORDER BY job;
24、STATS_BINOMIAL_TEST( expr1 , expr2 , p,
TWO_SIDED_PROB|EXACT_PROB|ONE_SIDED_PROB_OR_MORE|ONE_SIDED_PROB_OR_LESS)
统计二项测试是一个精确概率测试用于二分变量,那里只有两个可能值存在。它测试一个样品之间的差异比例和给定的比例
25、STATS_CROSSTAB (expr1 , expr2,
CHISQ_OBS|CHISQ_SIG|CHISQ_DF|PHI_COEFFICIENT|CRAMERS_V|CONT_COEFFICIENT|
COHENS_K
)
用于分析两个变量
26、STATS_F_TEST ( expr1, expr2,
[STATISTIC|DF_NUM|DF_DEN|ONE_SIDED_SIG|,expr3] |TWO_SIDED_SIG)
测试两个方差是否有明显的不同
27、STATS_KS_TEST (expr1 , expr2,STATISTIC|SIG)
是柯尔莫哥洛夫斯米尔诺夫函数比较两个样品测试他们是否来自相同的总体或有
相同分布的总体
28、STATS_MODE ( expr )
统计模式需要一组值作为它的参数并且返回发生以最大的频率
Select Deptno, Stats_Mode(Sal)
FROM emp
Group By deptno
ORDER BY deptno, stats_mode(sal);
29、STATS_MW_TEST (expr1 , expr2,STATISTIC|U_STATISTIC|ONE_SIDED_SIG , expr3|
TWO_SIDED_SIG)
一个曼惠特尼测试比较两个独立样本来测试该无效假设,这两个种群具有相同的分布函数与替代并且假设这两个分布函数是不同的
30、STATS_ONE_WAY_ANOVA( expr1 , expr2,
SUM_SQUARES_BETWEEN|SUM_SQUARES_WITHIN|DF_BETWEEN|DF_WITHIN|MEAN_SQUARES_BETWEEN|MEAN_SQUARES_WITHIN|F_RATIO|SIG)
单向方差分析函数(统计一维方差分析)测试差异在意味着(为团体或变量),通过比较两种统计学意义不同的估计方差
31、STATS_T_TEST_*
相关函数:
■ STATS_T_TEST_ONE: A one-sample t-test
■ STATS_T_TEST_PAIRED: A two-sample, paired t-test (also known as acrossed
t-test)
■ STATS_T_TEST_INDEP: A t-test of two independent groups with thesame
variance (pooled variances)
■ STATS_T_TEST_INDEPU: A t-test of two independent groups withunequal
variance (unpooled variances)
语法：
STATS_T_TEST_INDEP|STATS_T_TEST_INDEPU|STATS_T_TEST_ONE|STATS_T_TEST_PAIRED
( expr1 , expr2,
[STATISTIC|ONE_SIDED_SIG|, expr3]|TWO_SIDED_SIG|DF)
32、STATS_WSR_TEST (expr1 , expr2,STATISTIC|ONE_SIDED_SIG|TWO_SIDED_SIG)
33、STDDEV (DISTINCT|ALLexpr ) OVER ( analytic_clause ) 返回样本标准偏差
Select Stddev(Sal) "Deviation"
FROM emp;
Select Ename, Sal,
Stddev(Sal) Over (Order By HireDate)"StdDev"
FROM emp
ORDER BY ename, sal, "StdDev";
34、STDDEV_POP ( expr ) OVER( analytic_clause )
总体标准偏差计算并返回总体方差的平方根
SELECT deptno, ename, sal,
STDDEV_POP(sal) OVER (PARTITION BY deptno) ASpop_std
From emp
ORDER BY deptno, ename, sal, pop_std;
35、STDDEV_SAMP ( expr )OVER ( analytic_clause )
计算累积样本标准偏差和返回样本方差的平方根
Select Deptno, Ename, Hiredate, Sal,
STDDEV_SAMP(sal) OVER (PARTITION BY deptnoORDER BY hiredate ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS cum_sdev
From emp
ORDER BY deptno, ename, hiredate, sal,cum_sdev;
36、SUM (DISTINCT|ALL expr) OVER ( analytic_clause ) 求和
Select Mgr, Ename, Sal,
SUM(sal) OVER (PARTITION BY mgr ORDER BY salRANGE UNBOUNDED PRECEDING) l_csum
From Emp
ORDER BY mgr, ename, sal, l_csum;
37、SYS_XMLAGG ( expr,fmt) 将查询结果生成一个Xml文档
Select Sys_Xmlagg(Sys_Xmlgen(ename)) Xmlagg
FROM emp;
38、VAR_POP ( expr ) OVER ( analytic_clause )
返回总体方差的一组数字[丢弃Null值]
39、VAR_SAMP ( expr ) OVER( analytic_clause )
返回样本方差的一组数字[丢弃Null值]
Select Var_Pop(Sal),Var_SAMP(Sal)
FROM emp;
40、VARIANCE (DISTINCT|ALLexpr ) OVER ( analytic_clause ) 返回回报方差
SELECT ename, sal, VARIANCE(sal) OVER (ORDERBY hiredate) "Variance"
FROM emp
ORDER BY ename, sal, "Variance";
41、XMLAGG (XMLType_instance order_by_clause) 返回Xml文档
Select Xmlelement("Department",Xmlagg(Xmlelement("Employee",E.Job||' '||E.Ename) Order By Ename)) As "Dept_list"
From emp E;
Select Xmlelement("Department",Xmlagg(Xmlelement("Employee",E.Job||' '||E.Ename))) As "Dept_list"
From emp E
GROUP BY e.deptno