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ORACLE 高级函数应用

原创 Linux操作系统 作者:冷月逐浪 时间:2011-08-24 23:05:06 0 删除 编辑
--声明:本培训涉及的业务不一定准确,只为了说明函数的功能:
ORACLE 高级函数应用
--分组函数
1、ROLLUP
--统计标准分组及相应维度的小计、合计
--从右到左递减:group by rollup(a,b,c) :  a,b,c ;  a,b(对c的小计)  ;  a(对b,c的小计)  ;  总计
--1)
CALL VPD_PKG.SET_CONTEXT_COMPID('-1');
SELECT A.VPD_COMPID,TO_CHAR(A.TTIME,'MM'),COUNT(*)
   FROM XTBILL2011 A
   GROUP BY ROLLUP(A.VPD_COMPID,TO_CHAR(A.TTIME,'MM'));
--2)部分rollup分组
--对标准分组后,对a.typeid进行小计
SELECT A.DWDH,A.YEAR,A.TYPEID,COUNT(*)
   FROM XTYWBILL A
   GROUP BY A.DWDH,A.YEAR,ROLLUP(A.TYPEID);
2、CUBE
--rollup只能对“从右到左递减”,如需要全方位的维度进行统计,需要用到cube函数
--1)
SELECT A.VPD_COMPID,TO_CHAR(A.TTIME,'MM'),COUNT(*)
   FROM XTBILL2011 A
   GROUP BY CUBE(A.VPD_COMPID,TO_CHAR(A.TTIME,'MM'));
--2) 部分cube:可以去掉合计与某些不需要的小计。
SELECT A.VPD_COMPID,TO_CHAR(A.TTIME,'MM'),COUNT(*)
   FROM XTBILL2011 A
   GROUP BY A.VPD_COMPID,CUBE(TO_CHAR(A.TTIME,'MM'));
  
3、GROUPING SETS
--说明:仅关注单列分组,某些维度的小计
--group by grouping sets(a,b,c)相当于group by a,group by b,group by c
--这三组的union all结果
--1)
SELECT A.VPD_COMPID,TO_CHAR(A.TTIME,'MM'),COUNT(*)
   FROM XTBILL2011 A
   GROUP BY GROUPING SETS(A.VPD_COMPID,TO_CHAR(A.TTIME,'MM'));
--2)部分grouping sets分组
--在group by的基础上进行小计,仅关注小计的情况
SELECT A.DWDH,A.YEAR,A.TYPEID,COUNT(*)
   FROM XTYWBILL A
   GROUP BY A.DWDH,GROUPING SETS(A.YEAR,A.TYPEID);
SELECT A.VPD_COMPID,TO_CHAR(A.TTIME,'MM'),COUNT(*)
   FROM XTBILL2011 A
   GROUP BY A.VPD_COMPID,GROUPING SETS(TO_CHAR(A.TTIME,'MM'));
4、CUBE,ROLLUP作为GROUPING SETS的参数
--grouping sets操作只对单列进行分组,而不提供合计的功能,如果需要grouping sets提供合计的功能,
--那么可以使用rollup或cube作为grouping sets的参数,比如下面的语句提供合计功能:
SELECT A.VPD_COMPID,TO_CHAR(A.TTIME,'MM') AS TTIME,COUNT(*)
   FROM XTBILL2011 A
   GROUP BY GROUPING SETS(ROLLUP(A.VPD_COMPID),ROLLUP(TO_CHAR(A.TTIME,'MM')));
--这条语句产生了两个合计行,因为rollup或cube作为grouping sets的参数,相当于对每个
--rollup与cube操作的union all。所以上面的语句等价于:
SELECT A.VPD_COMPID,NULL AS TTIME,COUNT(*)
   FROM XTBILL2011 A
   GROUP BY ROLLUP(A.VPD_COMPID)
UNION ALL
SELECT NULL,TO_CHAR(A.TTIME,'MM'),COUNT(*)
   FROM XTBILL2011 A
   GROUP BY ROLLUP(TO_CHAR(A.TTIME,'MM'));
  
5、组合列分组简介:
--分组方式: rollup(a,b,c)<=>group by a,b,c; group by a,b; group by null
--分组方式: rollup(a,(b,c))<=>group by a,b,c; group by a; group by null
--分组方式: rollup(a,b),rollup(c)<=>group by a,b,c; group by a,b; group by a,c; group by a; group by c; group by null
--分组方式: rollup(a,b),grouping sets(c)<=>group by a,b,c; group by a,c; group by c
--分组方式: rollup(a),rollup(b),rollup(c)<=>group by a; group by b; group by c; group by a,b; group by a,c; group by b,c; group by a,b,c; group by null
6、GROUPING函数
--为了区别哪些是小计,grouping函数派上用场了!
SELECT A.VPD_COMPID,TO_CHAR(A.TTIME,'MM'),COUNT(*),GROUPING(A.VPD_COMPID),GROUPING(TO_CHAR(A.TTIME,'MM')),
   DECODE(GROUPING(A.VPD_COMPID),1,'所有单位',A.VPD_COMPID) VPD_COMPID,
   DECODE(TO_CHAR(A.TTIME,'MM'),1,'所有月份',TO_CHAR(A.TTIME,'MM')) TTIME  
   FROM XTBILL2011 A
   GROUP BY ROLLUP(A.VPD_COMPID,TO_CHAR(A.TTIME,'MM'));
--过滤某些分组结果
SELECT A.VPD_COMPID,TO_CHAR(A.TTIME,'MM'),COUNT(*),GROUPING(A.VPD_COMPID),GROUPING(TO_CHAR(A.TTIME,'MM')),
   DECODE(GROUPING(A.VPD_COMPID),1,'所有单位',A.VPD_COMPID) VPD_COMPID,
   DECODE(TO_CHAR(A.TTIME,'MM'),1,'所有月份',TO_CHAR(A.TTIME,'MM')) TTIME  
   FROM XTBILL2011 A
   GROUP BY ROLLUP(A.VPD_COMPID,TO_CHAR(A.TTIME,'MM'))
   HAVING GROUPING(A.VPD_COMPID)=1 OR GROUPING(TO_CHAR(A.TTIME,'MM'))=0;
7、GROUPING_ID函数
--可用rollup或cube与grouping_id组合运用,过滤出想要的分组统计信息
SELECT A.VPD_COMPID,TO_CHAR(A.TTIME,'MM'),GROUPING_ID(A.VPD_COMPID,TO_CHAR(A.TTIME,'MM')),COUNT(*)
   FROM XTBILL2011 A
   GROUP BY CUBE(A.VPD_COMPID,TO_CHAR(A.TTIME,'MM'))
   HAVING GROUPING_ID(A.VPD_COMPID,TO_CHAR(A.TTIME,'MM'))=2;  --1,2,3,0
--GROUPING_ID(a,b,c)过滤分组结果
分组级别   位向量    GROUPING_ID结果
a,b,C      0 0 0     0
a,B        0 0 1     1
A          0 1 1     3
汇总       1 1 1     7
8、GROUP_ID函数
--判断重复的分组
SELECT A.VPD_COMPID,TO_CHAR(A.TTIME,'MM') AS TTIME,GROUP_ID() ID,COUNT(*)
   FROM XTBILL2011 A
   GROUP BY GROUPING SETS(ROLLUP(A.VPD_COMPID),ROLLUP(TO_CHAR(A.TTIME,'MM')))
  -- HAVING GROUP_ID()=0;
 
9、实例应用说明:
DROP TABLE T;
CREATE TABLE t(
  ORDER_DATE DATE,  --订购日期
  ORDER_NO   NUMBER,  --订购号
  ORDER_BOOK  VARCHAR2(10),  --订购书籍
  ORDER_FEE   NUMBER,  --订单总金额
  ORDER_NUM   NUMBER
);
INSERT INTO T
  SELECT TO_DATE('2010-05-01','YYYY-MM-DD')+LEVEL,
  TRUNC(DBMS_RANDOM.value*1000),
  'book1',100+LEVEL,LEVEL
  FROM DUAL
  CONNECT BY LEVEL<5;
INSERT INTO T
  SELECT TO_DATE('2010-06-01','YYYY-MM-DD')+LEVEL,
  TRUNC(DBMS_RANDOM.value*1000),
  'book2',200+LEVEL,LEVEL
  FROM DUAL
  CONNECT BY LEVEL<5;
--要求:每组order_book内,按日期升序排列(order_no排序不管),常规分组在前,小计在后,合计最后。
SELECT DECODE(GROUPING_ID(ORDER_DATE,ORDER_NO,ORDER_BOOK),6,ORDER_BOOK||'小计',
  7,'合计',
  TO_CHAR(ORDER_DATE,'YYYY-MM-DD')
  ) ORDER_DATE1,
  ORDER_NO,
  DECODE(GROUPING_ID(ORDER_DATE,ORDER_NO,ORDER_BOOK),6,NULL,ORDER_BOOK) ORDER_BOOK1,
  SUM(ORDER_FEE) ORDER_FEE,
  SUM(ORDER_NUM) ORDER_NUM
 FROM T
 GROUP BY ROLLUP(ORDER_BOOK,(ORDER_DATE,ORDER_NO))
 ORDER BY ORDER_BOOK,ORDER_DATE;

--二、分析函数
--over()开窗函数  按compid分组,按ttime排序,对记录的一个递增统计处理
SELECT COUNT(SUMMONEY) OVER(PARTITION BY COMPID ORDER BY TTIME) CNT_SAL,
  SUm(SUMMONEY) OVER(PARTITION BY COMPID ORDER BY TTIME) SUM_SAL,
  MAX(SUMMONEY) OVER(PARTITION BY COMPID ORDER BY TTIME) MAX_SAL,
  MIN(SUMMONEY) OVER(PARTITION BY COMPID ORDER BY TTIME) MIN_SAL,
  AVG(SUMMONEY) OVER(PARTITION BY COMPID ORDER BY TTIME) AVG_SAL
 FROM XTYWBILL WHERE COMPID IN ('2601','2602');
--1、rows,range改变窗口范围的函数:
--窗口范围为该分区的第一行和该分区的最后一行
--sum(summoney) over(partition by compid order by ttime
  -- rows between unbounded preceding and unbounded following) sum_1
--窗口范围为该分区内大于本记录ttime-365天,并且截止到当前记录的所有的金额累计
--sum(summoney) over(partition by compid order by ttime
  -- range 365/*value_expr*/ preceding) sum_2
--2、keep的用法
SELECT BILLID,VPD_COMPID,TTIME,ZJE,
  DENSE_RANK() OVER(PARTITION BY VPD_COMPID ORDER BY TTIME) DENSE_RANK,
  MIN(ZJE) KEEP(DENSE_RANK FIRST ORDER BY TTIME) OVER(PARTITION BY VPD_COMPID) MIN_FIRST,
  MIN(ZJE) KEEP(DENSE_RANK LAST ORDER BY TTIME) OVER(PARTITION BY VPD_COMPID) MIN_LAST,
  MAX(ZJE) KEEP(DENSE_RANK LAST ORDER BY TTIME) OVER(PARTITION BY VPD_COMPID) MAX_LAST
    FROM XTBILL2011;
--min(zje) dense_rank first order by ttime 是从时间最早的记录中找到最小的金额.
--max(zje) dense_rank last order by ttime 是从时间最晚的记录中找到最大的金额.
--注意:keep只能与dense_rank first\dense_rank last搭配使用.
--3、统计函数:
SELECT BILLID,VPD_COMPID,TTIME,ZJE,
  MIN(ZJE) OVER(PARTITION BY VPD_COMPID ORDER BY TTIME) AS COMP_MIN,
  MAX(ZJE) OVER(PARTITION BY VPD_COMPID ORDER BY TTIME) AS COMP_MAX,
  AVG(ZJE) OVER(PARTITION BY VPD_COMPID ORDER BY TTIME) AS COMP_AVG,
  SUM(ZJE) OVER(PARTITION BY VPD_COMPID ORDER BY TTIME) AS COMP_SUM,
  COUNT(*) OVER(PARTITION BY VPD_COMPID ORDER BY ZJE) AS COUNT_BY,
  COUNT(*) OVER(PARTITION BY VPD_COMPID ORDER BY ZJE RANGE BETWEEN 50 PRECEDING AND 150 FOLLOWING) AS BY_RANGE
 FROM XTBILL2011;
 
--4、排序函数:
--问:rank()\dense_rank()区别:
RANK()  DENSE_RANK()
1       1
1       1
3       2
--LOG(zje,1,0) --找到前面记录的值,1:表示找前一个的值,0:表示找不到 默认的值
--LEAD(zje,1,) --找到后面记录的值,1:表示找前一个的值,0:表示找不到 默认的值
--first_value() --取出该窗口的第一个值。
--last_value() --取该窗口最后一个值,注意是按渐进顺序来的,都是这样!
--null值排最后,作为最大值列
SELECT BILLID,VPD_COMPID,TTIME,ZJE,
  /*RANK() OVER(PARTITION BY VPD_COMPID ORDER BY ZJE) AS RANK,
  DENSE_RANK() OVER(PARTITION BY VPD_COMPID ORDER BY ZJE) AS DENSE_RANK,
  MIN(ZJE) KEEP(DENSE_RANK FIRST ORDER BY TTIME) OVER(PARTITION BY VPD_COMPID) WORST,
  MAX(ZJE) KEEP(DENSE_RANK LAST ORDER BY TTIME) OVER(PARTITION BY VPD_COMPID) BEST,
  LAG(ZJE,1,0) OVER(ORDER BY TTIME) AS PREV_ZJE,
  LEAD(ZJE,1,0) OVER(ORDER BY TTIME) AS NEXT_SAL,*/
  FIRST_VALUE(BILLID) OVER(PARTITION BY VPD_COMPID ORDER BY ZJE) AS FIRST_VALUE_ASC,
  FIRST_VALUE(BILLID) OVER(PARTITION BY VPD_COMPID ORDER BY NVL(ZJE,0) DESC) AS FIRST_VALUE_DESC,
  LAST_VALUE(BILLID) OVER(PARTITION BY VPD_COMPID ORDER BY NVL(ZJE,0)) AS LAST_VALUE_ASC,
  LAST_VALUE(BILLID) OVER(PARTITION BY VPD_COMPID ORDER BY ZJE DESC) AS LAST_VALUE_DESC,
  ROW_NUMBER() OVER(PARTITION BY VPD_COMPID ORDER BY BILLID) AS ROW_NUMBER
 FROM XTBILL2011 ORDER BY VPD_COMPID,ZJE DESC;
 
--5、ratio_to_report() 函数
--记录,所占的百分比
SELECT BILLID,VPD_COMPID,TTIME,ZJE,
  RATIO_TO_REPORT(ZJE) OVER()
 FROM XTBILL2011;
 
 
三、树查询相关的函数
--1、ORDER SIBLINGS BY  先按上级的compid排序,再按下级的compid排序。
--2、level与rpad\lpad组合应用,构造可通的层级
--3、CONNECT_BY_ISLEAF 判断当前结点是否为叶子结点,0表示为非叶子结点,1则表示为叶子结点
 --(如果不存在下级节点就是路子节点)
--4、CONNECT_BY_ROOT 列出树的根结点对应的字段值,需与字段值组合使用
--5、SYS_CONNECT_BY_PATH 函数就是从start with 开始的地方开始遍历,并记下其遍历到的节点,
  --  start with 开始的地方被视为根节点,将遍历到的路径根据函数中的分隔符,组成一个新的
  --  字符串。
 SELECT LEVEL,LPAD(' ',(LEVEL-1)*3)||A.COMPID,CONNECT_BY_ISLEAF,
   CONNECT_BY_ROOT COMPNAME ROOT_COMPNAME,CONNECT_BY_ISCYCLE "CYCLE",
   SYS_CONNECT_BY_PATH(COMPID,'/') FORMAT_COMPID,
   SYS_CONNECT_BY_PATH(COMPNAME,'->') FORMAT_COMPNAME,
   A.*
   FROM COMPANYINFO A
  START WITH A.COMPID = '0000'
 CONNECT BY NOCYCLE PRIOR A.COMPID = A.PCOMPID
 ORDER SIBLINGS BY COMPID;
 SELECT * FROM COMPANYINFO WHERE COMPID='0000' FOR UPDATE;
--with关键字与树查询组合应用例子:
--查询与compid=’0001‘的同级节点
WITH COMPANYINFO_TMP AS
(SELECT LEVEL LEV,LPAD(' ',(LEVEL-1)*3)||A.COMPID,CONNECT_BY_ISLEAF,
   A.*
   FROM COMPANYINFO A 
  START WITH A.COMPID = '0000'
 CONNECT BY PRIOR A.COMPID = A.PCOMPID
 )
SELECT * FROM COMPANYINFO_TMP
  WHERE LEV=(SELECT LEV FROM COMPANYINFO_TMP
    WHERE COMPID='0001') ORDER BY COMPID;
   
四、其它:
NVL(a,b);    --若a为null,则返回b,否则返回a(即不转换)
NVL2(a,b,c); --不管a是不是Null都要转换,如果为空,返回c,否则返回b.
NULLIF(a,b); --判断a与b是否相等,若相等则返回null,不支持类型自动转换。
COALESC(a,b,...,n);  --从左到右返回第1个非null值,若所有的列表元素都为null,则返回null.它有短路计算功能,
  --比如,a为null,b非null,则返回b的值,不再计算下一个值。
DECODE\SIGN;
--应用例子:
WITH T AS
(SELECT LEVEL ID
  FROM DUAL
  CONNECT BY LEVEL<10
 )
SELECT ID,
  DECODE(-1,SIGN(ID-5),'low',
             SIGN(ID-8),'mid',
             'high') RESULTS
  FROM T;
--decode的常用应用之一是实现固定行转列:
--下面的一decode的综合应用:查询借货不平衡的数据
CALL VPD_PKG.SET_CONTEXT_COMPID('-1') ;
SELECT BILLID,SUM(DECODE(BZJD,1,TMONEYF,0)) AS DFJE,SUM(DECODE(BZJD,1,0,TMONEYF)) AS JFJE
  FROM (SELECT A.BILLID,DECODE(A.CXBZ,1,1-A.BZJD,A.BZJD) AS BZJD,SUM(DECODE(A.CXBZ,1,-1*A.TMONEYF,A.TMONEYF)) AS TMONEYF
          FROM XTBILLMX2010 A,XTBILL2010 B
          WHERE B.BILLID=A.BILLID AND B.BZWC=1
          GROUP BY A.BILLID,DECODE(A.CXBZ,1,1-A.BZJD,A.BZJD))
  GROUP BY BILLID
  HAVING SUM(DECODE(BZJD,1,TMONEYF,0))<>SUM(DECODE(BZJD,1,0,TMONEYF));
 

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