Oracle使用递归获得首级和末级的内容

原创于 2015-06-01 09:25:29 发布 · 2.1k 阅读

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本文介绍了如何在Oracle数据库中使用递归查询（START WITH...CONNECT BY）来获取树形结构数据的根节点（root_id为0）和叶子节点（connect_by_isleaf = 1）。创建了一个名为t2的表格，插入了多条记录，并展示了如何从t2中筛选出根节点和叶子节点。此外，还展示了如何通过t3表来限制查询的起始节点。

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create table t2(
root_id number,
id number,
name varchar(5),
description varchar(10)
);
insert into t2(root_id,id,name,description) values(0,1,'a','aaa');
insert into t2(root_id,id,name,description) values(1,2,'a1','aaa1');
insert into t2(root_id,id,name,description) values(1,3,'a2','aaa2');
insert into t2(root_id,id,name,description) values(0,4,'b','bbb');
insert into t2(root_id,id,name,description) values(4,5,'b1','bbb1');
insert into t2(root_id,id,name,description) values(4,6,'b2','bbb2');
insert into t2(root_id,id,name,description) values(6,7,'7b2','bbb2');
insert into t2(root_id,id,name,description) values(-1,-2,'-a','-aaa');
insert into t2(root_id,id,name,description) values(-2,-5,'-a','-aaa');
create table t3(id number);
insert into t3(id)values(7);
insert into t3(id)values(3);insert into t3(id)values(6);
select * from t2
select substr(sys_connect_by_path(id,':'),2,2),connect_by_isleaf,T2.* from t2
where connect_by_isleaf = 1
start with id in (select id from t2)
connect by prior root_id = id