Oracle 11g中CTE應用示例

關於SQL SERVER中的CTE中的CTE應用，請看這里：http://www.cnblogs.com/downmoon/archive/2009/10/23/1588405.html

其實，ORACLE的CTE語法完全一樣，看示例：

一、創建示例數據表如下：

declare 
      tableExistedCount  number; 
begin 
      select count(1) into tableExistedCount  from user_tables where TABLE_NAME ='DemoOrganization';
      if   tableExistedCount =1   then 
         execute immediate ' drop table DemoOrganization cascade constraints';
      end   if; 
end;

/*==============================================================*/
/* Table: DemoOrganization                                      */
/*==============================================================*/
create table DemoOrganization 
(
   OrgID                NUMBER(20,0)         not null,
   OrgCode              VARCHAR2(100),
   OrgName              NVARCHAR2(100),
   OrgPath              VARCHAR2(500),
   ParentID             INTEGER,
   OLevel               INTEGER              default 0,
   OrderID              NUMBER(10,0),
   CurState             INTEGER              default 0,
   AddUser              VARCHAR2(50),
   AddTime              DATE,
   constraint PK_DEMOORGANIZATION primary key (OrgID)
);

comment on table DemoOrganization is
'演示組織機構';

comment on column DemoOrganization.OrgID is
'機構ID';

comment on column DemoOrganization.OrgCode is
'機構編碼';

comment on column DemoOrganization.OrgName is
'機構名稱';

comment on column DemoOrganization.OrgPath is
'機構路徑';

comment on column DemoOrganization.ParentID is
'上級ID';

comment on column DemoOrganization.OLevel is
'級別';

comment on column DemoOrganization.OrderID is
'排序';

comment on column DemoOrganization.CurState is
'當前狀態';

comment on column DemoOrganization.AddUser is
'創建人';

comment on column DemoOrganization.AddTime is
'創建時間';

並插入測試數據：

drop sequence SEQ_DEMOORGANIZATION;
-- Create sequence 
create sequence SEQ_DEMOORGANIZATION
minvalue 1
maxvalue 999999999999999
start with 1
increment by 1
cache 201;

create or replace trigger TRI_SEQ_DEMOORGANIZATION
before insert on DEMOORGANIZATION

for each row
begin
select SEQ_DEMOORGANIZATION.NEXTVAL into:new.ORGID from dual;
end;

truncate table DEMOORGANIZATION;

INSERT INTO DEMOORGANIZATION(ORGNAME,OLEVEL,ORGPATH,PARENTID ,ADDTIME ,ADDUSER, ORDERID  ,CURSTATE)
select '組織機構1',1,'0',0,sysdate,'testUser',13,0  from dual union all
select '組織機構2',1,'0',0,sysdate,'testUser',12,0  from dual union all
select '組織機構3',1,'0',0,sysdate,'testUser' ,10,0  from dual union all
select '組織機構4',2,'1',1,sysdate,'testUser' ,19,0  from dual union all
select '組織機構5',2,'2',2,sysdate,'testUser' ,17,0  from dual union all
select '組織機構6',3,'1/4',4,sysdate,'testUser' ,16,0  from dual union all
select '組織機構7',3,'1/4',4,sysdate,'testUser' ,4,0  from dual union all
select '組織機構8',3,'2/5',5,sysdate,'testUser' ,3, 0 from dual union all
select '組織機構9',4,'1/4/6',6,sysdate,'testUser' ,5,0  from dual union all
select '組織機構10',4,'1/4/6',6,sysdate,'testUser' ,63,0  from dual union all
select '組織機構11',4,'1/4/6',6,sysdate,'testUser' ,83,0  from dual union all
select '組織機構12',4,'2/5/8',8,sysdate,'testUser' ,3,0  from dual union all
select '組織機構13',4,'2/5/8',8,sysdate,'testUser', 1,0  from dual;

select * from DEMOORGANIZATION;

二、示例：

1、--查詢ORGID為2的機構包含所有子機構，且級別不大於2

WITH SimpleRecursive(ORGNAME, ORGID, ORGPATH,PARENTID,OLEVEL)
    AS
(SELECT ORGNAME, ORGID, ORGPATH,PARENTID,0  FROM DEMOORGANIZATION WHERE ORGID = 2
UNION ALL
SELECT P.ORGNAME, P.ORGID, P.ORGPATH,P.PARENTID,P.OLEVEL+1
 FROM DEMOORGANIZATION  P  INNER JOIN
 SimpleRecursive A ON A.ORGID = P.PARENTID
)
SELECT sr.ORGNAME as ORGNAME, c.ORGNAME as PARENTIDName,sr.ORGPATH as PARENTIDCode
FROM SimpleRecursive sr inner join DEMOORGANIZATION c
on sr.PARENTID=c.ORGID
where c.OLEVEL<=2

2、--查詢ORGID為2的機構包含所有子機構，且級別不大於3

SELECT ORGNAME as ORGNAME,
(Select ORGNAME from DEMOORGANIZATION s where c.PARENTID=s.ORGID) as PARENTNAME,
ORGPATH as ORGPATH,OLEVEL
from DEMOORGANIZATION c where ORGPATH like'2/%' and OLEVEL<=3

3、--查找某個ORGID為12的部門對應的所有樹級部門

SELECT ORGID, OLEVEL, ORGNAME, PARENTID
  FROM DEMOORGANIZATION D
 START WITH ORGID IN (SELECT ORGID
                        FROM DEMOORGANIZATION
                       WHERE ORGID = 12
                         AND ROWNUM = 1)
CONNECT BY PRIOR D.PARENTID = ORGID;

4、--查找某個ORGID為12的部門對應的頂級部門             

SELECT *
 FROM (SELECT FIRST_VALUE(ORGNAME) OVER(ORDER BY LEVEL DESC ROWS UNBOUNDED PRECEDING) AS FIRSTID
         FROM DEMOORGANIZATION
        START WITH ORGID = 12
       CONNECT BY PRIOR PARENTID = ORGID) T
WHERE ROWNUM = 1