SYS_CONNECT_BY_PATH函数的用法

1、脚本

create table T_TREE(
  S_ID   NUMBER,
  F_ID   NUMBER,
  S_NAME VARCHAR2(20)
);
comment on column T_TREE.S_ID
  is '本节点ID';
comment on column T_TREE.F_ID
  is '父节点ID';
comment on column T_TREE.S_NAME
  is '本节点名称';
insert into t_tree values(1,null,'root');
insert into t_tree values(2,1,'node-010');
insert into t_tree values(3,1,'node-020');
insert into t_tree values(4,3,'node-011');
insert into t_tree values(5,4,'node-011');
commit;

 2、用SYS_CONNECT_BY_PATH执行SQL语句

SELECT CONNECT_BY_ISLEAF ISLEAF,
       S_NAME,
       LTRIM(SYS_CONNECT_BY_PATH(S_NAME, '$'), '$') PATH
  FROM T_TREE
CONNECT BY PRIOR S_ID = F_ID
 START WITH F_ID IS NULL;

 

其实SYS_CONNECT_BY_PATH这个函数是oracle9i才新提出来的！它一定要和connect by子句合用！

第一个参数是形成树形式的字段，第二个参数是父级和其子级分隔显示用的分隔符！
START WITH 代表你要开始遍历的的节点！CONNECT BY PRIOR 是标示父子关系的对应！

其中CONNECT_BY_ISLEAF ISLEAF 是判断数据是否是叶节点，如果是的话 值是1，还有子节点的话值是0；

3、查询结果