sqlserver实现树形结构递归查询(无限极分类)的方法

sql Server 2005开始，我们可以直接通过CTE来支持递归查询,CTE即公用表表达式

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公用表表达式（CTE），是一个在查询中定义的临时命名结果集将在from子句中使用它。每个CTE仅被定义一次（但在其作用域内可以被引用任意次），并且在该查询生存期间将一直生存。可以使用CTE来执行递归操作。创建的语法是：

rush:sql;"> with () as( ) select * from

1、生成数据

rush:sql;"> --菜单目录结构表 create table tb_menu( id int not null,--主键id title varchar(50),--标题 parent int --parent id ); --父菜单 insert into tb_menu(id,title,parent) values(1,'父菜单1',null); insert into tb_menu(id,parent) values(2,'父菜单2',parent) values(3,'父菜单3',parent) values(4,'父菜单4',parent) values(5,'父菜单5',null); --一级菜单 insert into tb_menu(id,parent) values(6,'一级菜单6',1); insert into tb_menu(id,parent) values(7,'一级菜单7',parent) values(8,'一级菜单8',parent) values(9,'一级菜单9',2); insert into tb_menu(id,parent) values(10,'一级菜单10',parent) values(11,'一级菜单11',parent) values(12,'一级菜单12',3); insert into tb_menu(id,parent) values(13,'一级菜单13',parent) values(14,'一级菜单14',parent) values(15,'一级菜单15',4); insert into tb_menu(id,parent) values(16,'一级菜单16',parent) values(17,'一级菜单17',parent) values(18,'一级菜单18',5); insert into tb_menu(id,parent) values(19,'一级菜单19',parent) values(20,'一级菜单20',5); --二级菜单 insert into tb_menu(id,parent) values(21,'二级菜单21',6); insert into tb_menu(id,parent) values(22,'二级菜单22',parent) values(23,'二级菜单23',7); insert into tb_menu(id,parent) values(24,'二级菜单24',parent) values(25,'二级菜单25',8); insert into tb_menu(id,parent) values(26,'二级菜单26',9); insert into tb_menu(id,parent) values(27,'二级菜单27',10); insert into tb_menu(id,parent) values(28,'二级菜单28',11); insert into tb_menu(id,parent) values(29,'二级菜单29',12); insert into tb_menu(id,parent) values(30,'二级菜单30',13); insert into tb_menu(id,parent) values(31,'二级菜单31',14); insert into tb_menu(id,parent) values(32,'二级菜单32',15); insert into tb_menu(id,parent) values(33,'二级菜单33',16); insert into tb_menu(id,parent) values(34,'二级菜单34',17); insert into tb_menu(id,parent) values(35,'二级菜单35',18); insert into tb_menu(id,parent) values(36,'二级菜单36',19); insert into tb_menu(id,parent) values(37,'二级菜单37',20);

--三级菜单
insert into tb_menu(id,parent) values(38,'三级菜单38',21);
insert into tb_menu(id,parent) values(39,'三级菜单39',22);
insert into tb_menu(id,parent) values(40,'三级菜单40',23);
insert into tb_menu(id,parent) values(41,'三级菜单41',24);
insert into tb_menu(id,parent) values(42,'三级菜单42',25);
insert into tb_menu(id,parent) values(43,'三级菜单43',26);
insert into tb_menu(id,parent) values(44,'三级菜单44',27);
insert into tb_menu(id,parent) values(45,'三级菜单45',28);
insert into tb_menu(id,parent) values(46,'三级菜单46',parent) values(47,'三级菜单47',29);
insert into tb_menu(id,parent) values(48,'三级菜单48',30);
insert into tb_menu(id,parent) values(49,'三级菜单49',31);
insert into tb_menu(id,parent) values(50,'三级菜单50',31);
commit;

2.查找所有上级节点

rush:sql;"> --查询树状结构某节点(44)的上级所有根节点

with cte_parent(id,parent)

as

(

--起始条件

select id,parent

from tb_menu

where id = 44 --列出子节点查询条件

union all

--递归条件

select a.id,a.title,a.parent

from tb_menu a

inner join

cte_parent b --执行递归，这里就要理解下了

on a.id=b.parent

)

select * from cte_parent;

3.查找下级节点带level

rush:sql;"> --查询树状结构某节点下的所有子节点(

with cte_child(id,parent,level)

as

(

--起始条件

select id,0 as level

from tb_menu

where id = 6--列出父节点查询条件

union all

--递归条件

select a.id,a.parent,b.level+1

from tb_menu a

inner join

cte_child b

on ( a.parent=b.id)

)

select * from cte_child;

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