Oracle递归查询树形数据实例代码（oracle 递归查询树状结构）怎么可以错过

文章摘要

这篇文章主要介绍了如何在MySQL数据库中创建并管理一个层级化的地理数据表。文章首先创建了`area_test`表，包含`id`、`parent_id`和`name`字段，并为其添加了主键约束。接着，通过多次`INSERT INTO`语句向表中插入了数据，构建了中国、省、市、区的层级结构，如插入了"中国"作为根节点，"河南省"和"北京市"作为其子节点，依此类推，最后插入了具体到"尚店镇"的数据。文章通过这些操作展示了如何通过数据库管理工具高效地构建地理层级关系。

create table area_test(
id number(10) not null,
parent_id number(10),
name varchar2(255) not null
);

alter table area_test add (constraint district_pk primary key (id));

insert into area_test (ID, PARENT_ID, NAME) values (1, null, ‘中国’);
insert into area_test (ID, PARENT_ID, NAME) values (11, 1, ‘河南省’);
insert into area_test (ID, PARENT_ID, NAME) values (12, 1, ‘北京市’);
insert into area_test (ID, PARENT_ID, NAME) values (111, 11, ‘郑州市’);
insert into area_test (ID, PARENT_ID, NAME) values (112, 11, ‘平顶山市’);
insert into area_test (ID, PARENT_ID, NAME) values (113, 11, ‘洛阳市’);
insert into area_test (ID, PARENT_ID, NAME) values (114, 11, ‘新乡市’);
insert into area_test (ID, PARENT_ID, NAME) values (115, 11, ‘南阳市’);
insert into area_test (ID, PARENT_ID, NAME) values (121, 12, ‘朝阳区’);
insert into area_test (ID, PARENT_ID, NAME) values (122, 12, ‘昌平区’);
insert into area_test (ID, PARENT_ID, NAME) values (1111, 111, ‘二七区’);
insert into area_test (ID, PARENT_ID, NAME) values (1112, 111, ‘中原区’);
insert into area_test (ID, PARENT_ID, NAME) values (1113, 111, ‘新郑市’);
insert into area_test (ID, PARENT_ID, NAME) values (1114, 111, ‘经开区’);
insert into area_test (ID, PARENT_ID, NAME) values (1115, 111, ‘金水区’);
insert into area_test (ID, PARENT_ID, NAME) values (1121, 112, ‘湛河区’);
insert into area_test (ID, PARENT_ID, NAME) values (1122, 112, ‘舞钢市’);
insert into area_test (ID, PARENT_ID, NAME) values (1123, 112, ‘宝丰市’);
insert into area_test (ID, PARENT_ID, NAME) values (11221, 1122, ‘尚店镇’);