加入两个层次结构查询以形成更大的层次结构
Joining two Hierarchical queries to form larger Hierarchy
我研究过这个问题,知道我不是第一个问这个问题的人,但我似乎无法理解。我创建了一个简单的示例,如果有人可以提供缺少的 link!
,我认为它会帮助我破解它
我有一个 table 区域,其中按层次结构包含大陆和国家/地区。
我还有一个 table 地方,其中包含层次结构中的城市和地标。此 table 包含一个区域 ID 列以加入区域 table。
create table areas
(
id NUMBER not null,
name VARCHAR2(200) not null,
parent_id NUMBER
);
-- Top Level
Insert into areas (id, name)
Values (1, 'Europe');
Insert into areas (id, name)
Values (2, 'Americas');
Insert into areas (id, name)
Values (3, 'Asia ex Japan');
Insert into areas (id, name)
Values (4, 'Japan');
-- Jurisdictions
Insert into areas (id, name, parent_id)
Values (5, 'UK', 1);
Insert into areas (id, name, parent_id)
Values (7, 'France', 1);
Insert into areas (id, name, parent_id)
Values (6, 'Germany', 1);
Insert into areas (id, name, parent_id)
Values (8, 'Italy', 1);
Insert into areas (id, name, parent_id)
Values (9, 'US', 2);
Insert into areas (id, name, parent_id)
Values (10, 'Australia', 3);
Insert into areas (id, name, parent_id)
Values (11, 'New Zealand', 3);
create table places
(
id NUMBER not null,
name VARCHAR2(200) not null,
area_id NUMBER,
parent_id NUMBER
);
Insert into places (id, name, area_id, parent_id)
Values (1, 'London', 5, NULL);
Insert into places (id, name, area_id, parent_id)
Values (2, 'Bath', 5, NULL);
Insert into places (id, name, area_id, parent_id)
Values (3, 'Liverpool', 5, NULL);
Insert into places (id, name, area_id, parent_id)
Values (4, 'Paris', 7, NULL);
Insert into places (id, name, area_id, parent_id)
Values (5, 'New York', 9, NULL);
Insert into places (id, name, area_id, parent_id)
Values (6, 'Chicago', 9, NULL);
Insert into places (id, name, area_id, parent_id)
Values (7, 'Kings Cross', 5, 1);
Insert into places (id, name, area_id, parent_id)
Values (8, 'Tower of London', 5, 1);
我可以像这样独立查询这些table:
SELECT a.*, level FROM areas a
start with parent_id is null
connect by prior id = parent_id
SELECT p.*, level FROM places p
start with parent_id is null
connect by prior id = parent_id
有人能告诉我最后一步将这些连接到一个具有四个级别的查询中吗?我多年来一直在使用 Oracle,但不知怎么的,这从来没有出现过!
如果在 table 的地方没有先验连接,只是一个带有区域 ID 的城市列表,这会更容易吗?
谢谢
是你需要的吗?
with src as (
select 'A' type, a.id, a.name, a.parent_id, null area_id from areas a
union all
select 'P', -p.id id, p.name, -p.parent_id parent_id, area_id from places p)
select
src.*, level
from
src
start with
type = 'A' and parent_id is null
connect by
parent_id = prior id or
parent_id is null and area_id = prior id
我研究过这个问题,知道我不是第一个问这个问题的人,但我似乎无法理解。我创建了一个简单的示例,如果有人可以提供缺少的 link!
,我认为它会帮助我破解它我有一个 table 区域,其中按层次结构包含大陆和国家/地区。
我还有一个 table 地方,其中包含层次结构中的城市和地标。此 table 包含一个区域 ID 列以加入区域 table。
create table areas
(
id NUMBER not null,
name VARCHAR2(200) not null,
parent_id NUMBER
);
-- Top Level
Insert into areas (id, name)
Values (1, 'Europe');
Insert into areas (id, name)
Values (2, 'Americas');
Insert into areas (id, name)
Values (3, 'Asia ex Japan');
Insert into areas (id, name)
Values (4, 'Japan');
-- Jurisdictions
Insert into areas (id, name, parent_id)
Values (5, 'UK', 1);
Insert into areas (id, name, parent_id)
Values (7, 'France', 1);
Insert into areas (id, name, parent_id)
Values (6, 'Germany', 1);
Insert into areas (id, name, parent_id)
Values (8, 'Italy', 1);
Insert into areas (id, name, parent_id)
Values (9, 'US', 2);
Insert into areas (id, name, parent_id)
Values (10, 'Australia', 3);
Insert into areas (id, name, parent_id)
Values (11, 'New Zealand', 3);
create table places
(
id NUMBER not null,
name VARCHAR2(200) not null,
area_id NUMBER,
parent_id NUMBER
);
Insert into places (id, name, area_id, parent_id)
Values (1, 'London', 5, NULL);
Insert into places (id, name, area_id, parent_id)
Values (2, 'Bath', 5, NULL);
Insert into places (id, name, area_id, parent_id)
Values (3, 'Liverpool', 5, NULL);
Insert into places (id, name, area_id, parent_id)
Values (4, 'Paris', 7, NULL);
Insert into places (id, name, area_id, parent_id)
Values (5, 'New York', 9, NULL);
Insert into places (id, name, area_id, parent_id)
Values (6, 'Chicago', 9, NULL);
Insert into places (id, name, area_id, parent_id)
Values (7, 'Kings Cross', 5, 1);
Insert into places (id, name, area_id, parent_id)
Values (8, 'Tower of London', 5, 1);
我可以像这样独立查询这些table:
SELECT a.*, level FROM areas a
start with parent_id is null
connect by prior id = parent_id
SELECT p.*, level FROM places p
start with parent_id is null
connect by prior id = parent_id
有人能告诉我最后一步将这些连接到一个具有四个级别的查询中吗?我多年来一直在使用 Oracle,但不知怎么的,这从来没有出现过!
如果在 table 的地方没有先验连接,只是一个带有区域 ID 的城市列表,这会更容易吗?
谢谢
是你需要的吗?
with src as (
select 'A' type, a.id, a.name, a.parent_id, null area_id from areas a
union all
select 'P', -p.id id, p.name, -p.parent_id parent_id, area_id from places p)
select
src.*, level
from
src
start with
type = 'A' and parent_id is null
connect by
parent_id = prior id or
parent_id is null and area_id = prior id