众所周知，目前的mysql版本中并不支持直接的递归查询，但是通过递归到迭代转化的思路，还是可以在一句SQL内实现树的递归查询的。这个得益于Mysql允许在SQL语句内使用@变量。以下是示例代码。
创建表格
CREATE TABLE `treenodes` (
`id` int , -- 节点ID
`nodename` varchar (60), -- 节点名称
`pid` int -- 节点父ID
);
插入测试数据
INSERT INTO `treenodes` (`id`, `nodename`, `pid`) VALUES
('1','A','0'),('2','B','1'),('3','C','1'),
('4','D','2'),('5','E','2'),('6','F','3'),
('7','G','6'),('8','H','0'),('9','I','8'),
('10','J','8'),('11','K','8'),('12','L','9'),
('13','M','9'),('14','N','12'),('15','O','12'),
('16','P','15'),('17','Q','15'),('18','R','3'),
('19','S','2'),('20','T','6'),('21','U','8');
查询语句
SELECT id AS ID,pid AS 父ID ,levels AS 父到子之间级数, paths AS 父到子路径 FROM (
SELECT id,pid,
@le:= IF (pid = 0 ,0,
IF( LOCATE( CONCAT('|',pid,':'),@pathlevel) > 0 ,
SUBSTRING_INDEX( SUBSTRING_INDEX(@pathlevel,CONCAT('|',pid,':'),-1),'|',1) +1
,@le+1) ) levels
, @pathlevel:= CONCAT(@pathlevel,'|',id,':', @le ,'|') pathlevel
, @pathnodes:= IF( pid =0,',0',
CONCAT_WS(',',
IF( LOCATE( CONCAT('|',pid,':'),@pathall) > 0 ,
SUBSTRING_INDEX( SUBSTRING_INDEX(@pathall,CONCAT('|',pid,':'),-1),'|',1)
,@pathnodes ) ,pid ) )paths
,@pathall:=CONCAT(@pathall,'|',id,':', @pathnodes ,'|') pathall
FROM treenodes,
(SELECT @le:=0,@pathlevel:='', @pathall:='',@pathnodes:='') vv
ORDER BY pid,id
) src
ORDER BY id
最后的结果如下：
ID 父ID 父到子之间级数 父到子路径
------ ------ ------------ ---------------
1 0 0 ,0
2 1 1 ,0,1
3 1 1 ,0,1
4 2 2 ,0,1,2
5 2 2 ,0,1,2
6 3 2 ,0,1,3
7 6 3 ,0,1,3,6
8 0 0 ,0
9 8 1 ,0,8
10 8 1 ,0,8
11 8 1 ,0,8
12 9 2 ,0,8,9
13 9 2 ,0,8,9
14 12 3 ,0,8,9,12
15 12 3 ,0,8,9,12
16 15 4 ,0,8,9,12,15
17 15 4 ,0,8,9,12,15
18 3 2 ,0,1,3
19 2 2 ,0,1,2
20 6 3 ,0,1,3,6
21 8 1 ,0,8
http://www.cnblogs.com/dukou/p/4691543.html
--创建表
DROP
TABLE
IF EXISTS `t_areainfo`;
CREATE
TABLE
`t_areainfo` (
`id`
int
(11)
NOT
'0'
AUTO_INCREMENT,
`
level
`
int
(11)
DEFAULT
'0'
,
`
name
`
varchar
(255)
DEFAULT
'0'
,
`parentId`
int
(11)
DEFAULT
'0'
,
`status`
int
(11)
DEFAULT
'0'
,
PRIMARY
KEY
(`id`)
) ENGINE=InnoDB AUTO_INCREMENT=65
DEFAULT
CHARSET=utf8;
|
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--初始数据
INSERT
INTO
`t_areainfo`
VALUES
(
'1'
,
'0'
,
'中国'
,
'0'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'2'
,
'0'
,
'华北区'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'3'
,
'0'
,
'华南区'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'4'
,
'0'
,
'北京'
,
'2'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'5'
,
'0'
,
'海淀区'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'6'
,
'0'
,
'丰台区'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'7'
,
'0'
,
'朝阳区'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'8'
,
'0'
,
'北京XX区1'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'9'
,
'0'
,
'北京XX区2'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'10'
,
'0'
,
'北京XX区3'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'11'
,
'0'
,
'北京XX区4'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'12'
,
'0'
,
'北京XX区5'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'13'
,
'0'
,
'北京XX区6'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'14'
,
'0'
,
'北京XX区7'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'15'
,
'0'
,
'北京XX区8'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'16'
,
'0'
,
'北京XX区9'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'17'
,
'0'
,
'北京XX区10'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'18'
,
'0'
,
'北京XX区11'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'19'
,
'0'
,
'北京XX区12'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'20'
,
'0'
,
'北京XX区13'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'21'
,
'0'
,
'北京XX区14'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'22'
,
'0'
,
'北京XX区15'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'23'
,
'0'
,
'北京XX区16'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'24'
,
'0'
,
'北京XX区17'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'25'
,
'0'
,
'北京XX区18'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'26'
,
'0'
,
'北京XX区19'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'27'
,
'0'
,
'北京XX区1'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'28'
,
'0'
,
'北京XX区2'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'29'
,
'0'
,
'北京XX区3'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'30'
,
'0'
,
'北京XX区4'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'31'
,
'0'
,
'北京XX区5'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'32'
,
'0'
,
'北京XX区6'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'33'
,
'0'
,
'北京XX区7'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'34'
,
'0'
,
'北京XX区8'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'35'
,
'0'
,
'北京XX区9'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'36'
,
'0'
,
'北京XX区10'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'37'
,
'0'
,
'北京XX区11'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'38'
,
'0'
,
'北京XX区12'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'39'
,
'0'
,
'北京XX区13'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'40'
,
'0'
,
'北京XX区14'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'41'
,
'0'
,
'北京XX区15'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'42'
,
'0'
,
'北京XX区16'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'43'
,
'0'
,
'北京XX区17'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'44'
,
'0'
,
'北京XX区18'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'45'
,
'0'
,
'北京XX区19'
,
'4'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'46'
,
'0'
,
'xx省1'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'47'
,
'0'
,
'xx省2'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'48'
,
'0'
,
'xx省3'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'49'
,
'0'
,
'xx省4'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'50'
,
'0'
,
'xx省5'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'51'
,
'0'
,
'xx省6'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'52'
,
'0'
,
'xx省7'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'53'
,
'0'
,
'xx省8'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'54'
,
'0'
,
'xx省9'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'55'
,
'0'
,
'xx省10'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'56'
,
'0'
,
'xx省11'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'57'
,
'0'
,
'xx省12'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'58'
,
'0'
,
'xx省13'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'59'
,
'0'
,
'xx省14'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'60'
,
'0'
,
'xx省15'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'61'
,
'0'
,
'xx省16'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'62'
,
'0'
,
'xx省17'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'63'
,
'0'
,
'xx省18'
,
'1'
,
'0'
);
INSERT
INTO
`t_areainfo`
VALUES
(
'64'
,
'0'
,
'xx省19'
,
'1'
,
'0'
);
|
采用function获取所有子节点的id
|
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--查询传入areaId及其以下所有子节点
DROP
FUNCTION
IF EXISTS queryChildrenAreaInfo;
CREATE
FUNCTION
`queryChildrenAreaInfo` (areaId
INT
)
RETURNS
VARCHAR
(4000)
BEGIN
DECLARE
sTemp
VARCHAR
(4000);
DECLARE
sTempChd
VARCHAR
(4000);
SET
sTemp =
'$'
;
SET
sTempChd =
cast
(areaId
as
char
);
WHILE sTempChd
is
not
NULL
DO
SET
sTemp = CONCAT(sTemp,
','
,sTempChd);
SELECT
group_concat(id)
INTO
sTempChd
FROM
t_areainfo
where
FIND_IN_SET(parentId,sTempChd)>0;
END
WHILE;
return
sTemp;
END
;
--调用方式
select
queryChildrenAreaInfo(1);
select
*
from
t_areainfo
where
FIND_IN_SET(id, queryChildrenAreaInfo(1));
|
https://zhidao.baidu.com/question/1303213320623933579.html
https://www.iteye.com/problems/100720