mysql实现类似oracle的connect by功能

浏览数：21 / 时间：2015年06月12日

1.生成测试表与数据:
create table mytest
(
id int primary key,
nodename varchar(20),
pid int
);
insert into mytest (id,nodename,pid)values( 1 ,‘A‘, 0);
insert into mytest (id,nodename,pid)values( 2 ,‘B‘, 1);
insert into mytest (id,nodename,pid)values( 3 ,‘C‘, 1);
insert into mytest (id,nodename,pid)values( 4 ,‘D‘, 2);
insert into mytest (id,nodename,pid)values( 5 ,‘E‘, 2);
insert into mytest (id,nodename,pid)values( 6 ,‘F‘, 3);
insert into mytest (id,nodename,pid)values( 7 ,‘G‘, 6);
insert into mytest (id,nodename,pid)values( 8 ,‘H‘, 0);
insert into mytest (id,nodename,pid)values( 9 ,‘I‘, 8);
insert into mytest (id,nodename,pid)values( 10 ,‘J‘, 8);
insert into mytest (id,nodename,pid)values( 11 ,‘K‘, 8);
insert into mytest (id,nodename,pid)values( 12 ,‘L‘, 9);
insert into mytest (id,nodename,pid)values( 13 ,‘M‘, 9);
insert into mytest (id,nodename,pid)values( 14 ,‘N‘,12);
insert into mytest (id,nodename,pid)values( 15 ,‘O‘,12);
insert into mytest (id,nodename,pid)values( 16 ,‘P‘,15);
insert into mytest (id,nodename,pid)values( 17 ,‘Q‘,15);

2.创建函数:
delimiter $$
CREATE FUNCTION `getParentList` (rootId VARCHAR (50)) RETURNS VARCHAR (1000)
BEGIN
DECLARE sParentList VARCHAR (1000) ;
DECLARE sParentTemp VARCHAR(1000);
SET sParentTemp =CAST(rootId AS CHAR);
WHILE sParentTemp IS NOT NULL DO
IF (sParentList IS NOT NULL) THEN
SET sParentList = CONCAT(sParentTemp,‘/‘,sParentList);
ELSE
SET sParentList = CONCAT(sParentTemp);
END IF;
SELECT GROUP_CONCAT(pid) INTO sParentTemp FROM mytest WHERE FIND_IN_SET(id,sParentTemp)>0;
END WHILE;
RETURN sParentList;
END$$
DELIMITER ;

3.测试验证:
set global log_bin_trust_function_creators=1;
SELECT id,pid,getParentList(id) FROM mytest;

mysql> SELECT id,pid,getParentList(id) FROM mytest;
+----+------+-------------------+
| id | pid | getParentList(id) |
+----+------+-------------------+
| 1 |    0 | 0/1               |
| 2 |    1 | 0/1/2             |
| 3 |    1 | 0/1/3             |
| 4 |    2 | 0/1/2/4           |
| 5 |    2 | 0/1/2/5           |
| 6 |    3 | 0/1/3/6           |
| 7 |    6 | 0/1/3/6/7         |
| 8 |    0 | 0/8               |
| 9 |    8 | 0/8/9             |
| 10 |    8 | 0/8/10            |
| 11 |    8 | 0/8/11            |
| 12 |    9 | 0/8/9/12          |
| 13 |    9 | 0/8/9/13          |
| 14 |   12 | 0/8/9/12/14       |
| 15 |   12 | 0/8/9/12/15       |
| 16 |   15 | 0/8/9/12/15/16    |
| 17 |   15 | 0/8/9/12/15/17    |
+----+------+-------------------+
17 rows in set (0.01 sec)