Oracle递归查询
一、创建数据
1.1、建立表与插入数据
CREATE TABLE DISTRICT ( ID NUMBER(10) NOT NULL, PARENT_ID NUMBER(10), NAME VARCHAR2(255 BYTE) NOT NULL ); ALTER TABLE DISTRICT ADD ( CONSTRAINT DISTRICT_PK PRIMARY KEY (ID)); ALTER TABLE DISTRICT ADD ( CONSTRAINT DISTRICT_R01 FOREIGN KEY (PARENT_ID) REFERENCES DISTRICT (ID)); insert into DISTRICT (id, parent_id, name) values (1, null, '四川省'); insert into DISTRICT (id, parent_id, name) values (2, 1, '巴中市'); insert into DISTRICT (id, parent_id, name) values (3, 1, '达州市'); insert into DISTRICT (id, parent_id, name) values (4, 2, '巴州区'); insert into DISTRICT (id, parent_id, name) values (5, 2, '通江县'); insert into DISTRICT (id, parent_id, name) values (6, 2, '平昌县'); insert into DISTRICT (id, parent_id, name) values (7, 3, '通川区'); insert into DISTRICT (id, parent_id, name) values (8, 3, '宣汉县'); insert into DISTRICT (id, parent_id, name) values (9, 8, '塔河乡'); insert into DISTRICT (id, parent_id, name) values (10, 8, '三河乡'); insert into DISTRICT (id, parent_id, name) values (11, 8, '胡家镇'); insert into DISTRICT (id, parent_id, name) values (12, 8, '南坝镇'); insert into DISTRICT (id, parent_id, name) values (13, 6, '大寨乡'); insert into DISTRICT (id, parent_id, name) values (14, 6, '响滩镇'); insert into DISTRICT (id, parent_id, name) values (15, 6, '龙岗镇'); insert into DISTRICT (id, parent_id, name) values (16, 6, '白衣镇'); commit;
二、start with connect by prior递归
2.1、查询所有子节点
SELECT * FROM district START WITH NAME ='巴中市' CONNECT BY PRIOR ID=parent_id
2.2、查询所有父节点
SELECT * FROM district START WITH NAME ='平昌县' CONNECT BY PRIOR parent_id=ID
只需要交换 id 与parent_id的位置即可
2.3、查询指定节点的,根节点
SELECT d.*, connect_by_root(d.id), connect_by_root(NAME) FROM district d WHERE NAME='平昌县' START WITH d.parent_id=1 --d.parent_id is null 结果为四川省 CONNECT BY PRIOR d.ID=d.parent_id
2.4、查询巴中市下行政组织递归路径
SELECT ID,parent_id,NAME, sys_connect_by_path(NAME,'->') namepath, LEVEL FROM district START WITH NAME='巴中市' CONNECT BY PRIOR ID=parent_id
三、with递归
3.1、with递归子类
WITH t (ID ,parent_id,NAME) --要有列名 AS( SELECT ID ,parent_id,NAME FROM district WHERE NAME='巴中市' UNION ALL SELECT d.ID ,d.parent_id,d.NAME FROM t,district d --要指定表和列表, WHERE t.id=d.parent_id ) SELECT * FROM t;
3.2、递归父类
WITH t (ID ,parent_id,NAME) --要有表 AS( SELECT ID ,parent_id,NAME FROM district WHERE NAME='通江县' UNION ALL SELECT d.ID ,d.parent_id,d.NAME FROM t,district d --要指定表和列表, WHERE t.parent_id=d.id ) SELECT * FROM t;