本文引用自ekong《Oracle Connect By Prior用法》
英语四级辅导
引用
ekong 的 Oracle Connect By Prior用法
Oracle Connect By用法
oracle中的lect语句可以用CONNECT BY PRIOR子句实现递归查询，connect by 是结构化查询中用到的，其基本语法是：
lect ... from <TableName>
where <Conditional-1>
start with <Conditional-2>
connect by <Conditional-3>
;
<Conditional-1>：过滤条件，用于对返回的所有记录进行过滤。
<Conditional-2>love the way you lie 翻译：查询结果重起始根结点的限定条件。
<Conditional-3>：连接条件
数据组织结构如下图：
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数据库表结构如下：杭州英语口语培训
create table t2(
root_id number,
id number,
name varchar(5),
description varchar(10)
);
最后的维加斯
inrt into t2(root_id,id,name,description) values(0,1,'a','aaa');
inrt into t2(root_id,id,name,description) values(1,2,'a1','aaa1');
inrt into t2(root_id,id,name,description) values(1,3,'a2','aaa2');
inrt into t2(root_id,id,name,description) values(0,4,'b','bbb');
inrt into t2(root_id,id,name,description) values(4,5,'b1','bbb1');
inrt into t2(root_id,id,name,description) values(4,6,'b2','bbb2');
获取完整树：
lect * from t2 start with root_id = 0 connect by prior id = root_id;
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获取特定子树：
lect * from t2 start with id = 1 connect by prior id = root_id;
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lect * from t2 start with id = 4 connect by prior id = root_id;湖南化妆培训学校
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如果connect by prior中的prior被省略，则查询将不进行深层递归。
如：
lect * from t2 start with root_id = 0 connect by id = root_id;
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lect * from t2 start with id = 1 connect by id = root_id;
如：timezone
amend500)this.width=500;" border="0">
hah>have five
