Sql where子句与connect by的交互，并创建查询以获取层次结构中的下一级

表:

资料

要求

汇总所有IT部门的工资：

类别工资

5,50

伊塞克，60岁

ITDBA，60岁

汇总公司各部门工资情况：

类别工资

它是170

市场，40

汇总所有ITDBA部门的工资：

类别工资

3,30

ITDBASQL，10

ITDbarc，20岁

您会注意到，我们正试图根据层次结构中的下一个级别进行汇总。如果任何emp已经是该级别的一部分，那么我们需要向员工展示

试问：

关注和疑问：

此查询是否在所有场景中都能正常工作。还有更好的方法吗？？ where条件如何与connect by交互。例如，在子查询中，我们使用parent_dept='IT'进行筛选，但是，当通过某些emp启动连接时，可能会使用parent_dept='ITDBASQL'，这也是它的一部分。我很难理解工作流程。 谢谢你的时间和帮助

还有更好的方法吗

这是一个等效的查询，每个表只需要一次表扫描。您需要确定您的查询或此查询对于您的数据/索引等是否更有效

Oracle 11g R2架构设置：

问题1：

:

您可以单独运行查询以了解它们正在执行的操作：

SELECT CONNECT_BY_ROOT( dept ) AS root_dept,
       h.*,
       LEVEL AS lvl,
       ROW_NUMBER() OVER ( PARTITION BY parent_dept ORDER BY ROWNUM ) AS rn
FROM   temp_hierarchy_define h
WHERE  parent_dept != dept
START WITH h.parent_dept = 'IT'
CONNECT BY NOCYCLE PRIOR h.dept = h.parent_dept

---

只列出层次结构中的所有行，并使用CONNECT_BY_ROOT获取层次结构分支根处的部门。“级别”和“行号”用于查找层次结构顶部的第一行。

谢谢您的回答。因为我的主表中有所有适当的索引，所以我的查询执行得很快。我主要担心的是我不理解where条件&通过交互连接，特别是在这种情况下。请你解释一下好吗？如果我们试着向公司部门查询，它会重复金额。@pOrinG Updated

Select 'COMPANY' dept   , 'COMPANY' parent_dept  From Dual Union All
Select 'IT'        , 'COMPANY'  From Dual Union All
Select 'MARKET'    , 'COMPANY'  From Dual Union All
Select 'ITSEC'     , 'IT'       From Dual Union All
Select 'ITDBA'     , 'IT'       From Dual Union All
Select 'ITDBAORC'  , 'ITDBA'    From Dual Union All
Select 'ITDBASQL'  , 'ITDBA'    From Dual

select 1 empid, 'Rohan-ITDBASQL' empname   ,'ITDBASQL' dept ,10 salary from dual union all
select 2, 'Raj-ITDBAORC'     ,'ITDBAORC'  ,20 from dual union all
select 3, 'Roy-ITDBA'        ,'ITDBA'     ,30 from dual union all
select 4, 'Ray-MARKET'       ,'MARKET'    ,40 from dual union all
select 5, 'Roopal-IT'        ,'IT'        ,50 from dual union all
select 6, 'Ramesh-ITSEC'     ,'ITSEC'     ,60 from dual 

Select Category,sum(salary) from (
Select 
NVL((Select dept.dept from temp_hierarchy_define dept
               Where dept.parent_dept = 'IT'
               And dept.dept != 'IT' 
               Start With dept.dept = emp.dept
               Connect by NOCYCLE dept.dept = Prior dept.parent_dept
               and prior dept.dept is not null),emp.empid) category,
emp.*
From temp_employee emp
Where emp.DEPT in
(Select dept.dept from temp_hierarchy_define dept
Start With dept.dept = 'IT' 
connect by nocycle prior dept.dept = dept.parent_dept) ) Group by Category

create table temp_hierarchy_define (
  dept varchar2(25), parent_dept varchar2(25));
create table temp_employee (
  empid number(1), empname varchar2(50), dept varchar2(25), salary number(10));

INSERT INTO temp_hierarchy_define( dept, parent_dept )
Select 'COMPANY'   , 'COMPANY'  From Dual Union All
Select 'IT'        , 'COMPANY'  From Dual Union All
Select 'MARKET'    , 'COMPANY'  From Dual Union All
Select 'ITSEC'     , 'IT'       From Dual Union All
Select 'ITDBA'     , 'IT'       From Dual Union All
Select 'ITDBAORC'  , 'ITDBA'    From Dual Union All
Select 'ITDBASQL'  , 'ITDBA'    From Dual;

INSERT INTO temp_employee( empid, empname, dept, salary )
select 1, 'Rohan-ITDBASQL'   ,'ITDBASQL'  ,10 from dual union all
select 2, 'Raj-ITDBAORC'     ,'ITDBAORC'  ,20 from dual union all
select 3, 'Roy-ITDBA'        ,'ITDBA'     ,30 from dual union all
select 4, 'Ray-MARKET'       ,'MARKET'    ,40 from dual union all
select 5, 'Roopal-IT'        ,'IT'        ,50 from dual union all
select 6, 'Ramesh-ITSEC'     ,'ITSEC'     ,60 from dual;

SELECT dept,
       SUM( salary )
FROM   (
  SELECT CASE
         WHEN lvl = 1 AND h.parent_dept = e.dept
         THEN CAST( e.empid AS VARCHAR2(25) )
         ELSE root_dept
         END AS dept,
         e.empid,
         e.salary
  FROM   ( SELECT CONNECT_BY_ROOT( dept ) AS root_dept,
                  h.*,
                  LEVEL AS lvl,
                  ROW_NUMBER() OVER ( PARTITION BY parent_dept ORDER BY ROWNUM ) AS rn
           FROM   temp_hierarchy_define h
           WHERE  parent_dept != dept
           START WITH h.parent_dept = 'IT'
           CONNECT BY NOCYCLE PRIOR h.dept = h.parent_dept
         ) h
         LEFT OUTER JOIN
         temp_employee e
         ON (  h.dept = e.dept
            OR ( h.parent_dept = e.dept AND h.lvl = 1 AND h.rn = 1)    
            )
)
GROUP BY dept

|  DEPT | SUM(SALARY) |
|-------|-------------|
| ITDBA |          60 |
|     5 |          50 |
| ITSEC |          60 |

SELECT CONNECT_BY_ROOT( dept ) AS root_dept,
       h.*,
       LEVEL AS lvl,
       ROW_NUMBER() OVER ( PARTITION BY parent_dept ORDER BY ROWNUM ) AS rn
FROM   temp_hierarchy_define h
WHERE  parent_dept != dept
START WITH h.parent_dept = 'IT'
CONNECT BY NOCYCLE PRIOR h.dept = h.parent_dept