正文
oracle和postgresql 递归查询父子关系记录语法区别
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oracle:
一、数据
db数据字段如下：
task_id task_name t.parent_task_id ***
*** *** *** ***
000001 t1 *** ***
000002 t11 000001 ***
000005 t12 000001 ***
000003 t111 000002 ***
000004 t1111 000003 ***
000006 t121 000005 ***
000007 t1211 000006 ***
*** *** *** ***
二、格式
Select * from …. Where [结果过滤条件语句]
Start with [and起始条件过滤语句]
Connect by prior [and中间记录过滤条件语句]
三、查找所有下级
select * from tablename start with id=1 connect by prior id=pid
注意：此sql能查找id=1的数据的所有下级，写sql语句时要注意，因为是从id开始查找下级，所以connect by prior 子句的条件是 id=pid
四、查找所有上级
select * from tablename start with id=5 connect by prior pid=id
因为是从id开始查找上级，所以connect by prior 子句的条件是pid=d
select t.task_id ,t.task_name ,t.parent_task_id
from t_task t
start with task_id=''
connect by prior task_id = parent_task_id;
五、显示结果
结果显示：
task_id task_name t.parent_task_id
000001 t1
000002 t11 000001
000003 t111 000002
000004 t1111 000003
000005 t12 000001
000006 t121 000005
000007 t1211 000006
postgresql:
查询父节点下所有的子节点
WITH recursive fileinfo
(pk_fi_id,
f_fi_parentid)
AS
(
SELECT
pk_fi_id ,
f_fi_parentid
FROM
t_fileinfo
WHERE
pk_fi_id = '92719f78-22d6-4db1-a484-dff34de76890'
UNION ALL
SELECT
mm.pk_fi_id ,
mm.f_fi_parentid
FROM
t_fileinfo AS mm
INNER JOIN fileinfo AS child ON mm.f_fi_parentid = child.pk_fi_id
)
SELECT
*
FROM fileinfo
