Orcal中显示树结构查询语句【包括子查父和父查子】

实际开发中可能会用到树状查询结果，语句如下：

select ID, LPAD(DEPT_NAME, LENGTH(DEPT_NAME) + (LEVEL * 2), '　') dept_name

from DEPT_INFO

where IS_DEL = 0

start with ID = 1

connect by prior ID = PAR_ID

程序解释:

LPAD(DEPT_NAME, LENGTH(DEPT_NAME) + (LEVEL * 2), '　') dept_name

LPAD:Oracle中查询关键字,

'　':为前面补齐的字符

Dept_name:为此结果列起的别名

start with ID = 1:树形开始

你还可以优化树的样式：

SELECT ID,
LPAD('|-', (level - 1) * 4, '　| ') || LPAD('『', 2) || dept_name ||
RPAD('』', 2) dept_name
from DEPT_INFO
where IS_DEL = 0
CONNECT BY PRIOR ID = PAR_ID
start with ID = 1

--从子查父

select *

from SYS_MODULE a

start with mod_id = 111

connect by prior PAR_ID = MOD_ID

--从父查所有子

select *

from SYS_MODULE a

start with par_id = 100

connect by prior MOD_ID = PAR_ID