小小编
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
--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`) |
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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 (\'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)BEGINDECLARE sTemp VARCHAR(4000);DECLARE sTempChd VARCHAR(4000);SET sTemp = \'$\';SET sTempChd = cast(areaId as char);return sTemp;END;--调用方式select queryChildrenAreaInfo(1);select * from t_areainfo where FIND_IN_SET(id, queryChildrenAreaInfo(1)); |
