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:

  with <name of you cte>(<column names>)  as(  <actual query>  )  select * from <name of your cte>

1、生成数据

  --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, title, parent) values(2, '父菜单2',null);   insert into tb_menu(id, title, parent) values(3, '父菜单3',null);   insert into tb_menu(id, title, parent) values(4, '父菜单4',null);   insert into tb_menu(id, title, parent) values(5, '父菜单5',null);   --一级菜单   insert into tb_menu(id, title, parent) values(6, '一级菜单6',1);   insert into tb_menu(id, title, parent) values(7, '一级菜单7',1);   insert into tb_menu(id, title, parent) values(8, '一级菜单8',1);   insert into tb_menu(id, title, parent) values(9, '一级菜单9',2);   insert into tb_menu(id, title, parent) values(10, '一级菜单10',2);   insert into tb_menu(id, title, parent) values(11, '一级菜单11',2);   insert into tb_menu(id, title, parent) values(12, '一级菜单12',3);   insert into tb_menu(id, title, parent) values(13, '一级菜单13',3);   insert into tb_menu(id, title, parent) values(14, '一级菜单14',3);   insert into tb_menu(id, title, parent) values(15, '一级菜单15',4);   insert into tb_menu(id, title, parent) values(16, '一级菜单16',4);   insert into tb_menu(id, title, parent) values(17, '一级菜单17',4);   insert into tb_menu(id, title, parent) values(18, '一级菜单18',5);   insert into tb_menu(id, title, parent) values(19, '一级菜单19',5);   insert into tb_menu(id, title, parent) values(20, '一级菜单20',5);   --二级菜单   insert into tb_menu(id, title, parent) values(21, '二级菜单21',6);   insert into tb_menu(id, title, parent) values(22, '二级菜单22',6);   insert into tb_menu(id, title, parent) values(23, '二级菜单23',7);   insert into tb_menu(id, title, parent) values(24, '二级菜单24',7);   insert into tb_menu(id, title, parent) values(25, '二级菜单25',8);   insert into tb_menu(id, title, parent) values(26, '二级菜单26',9);   insert into tb_menu(id, title, parent) values(27, '二级菜单27',10);   insert into tb_menu(id, title, parent) values(28, '二级菜单28',11);   insert into tb_menu(id, title, parent) values(29, '二级菜单29',12);   insert into tb_menu(id, title, parent) values(30, '二级菜单30',13);   insert into tb_menu(id, title, parent) values(31, '二级菜单31',14);   insert into tb_menu(id, title, parent) values(32, '二级菜单32',15);   insert into tb_menu(id, title, parent) values(33, '二级菜单33',16);   insert into tb_menu(id, title, parent) values(34, '二级菜单34',17);   insert into tb_menu(id, title, parent) values(35, '二级菜单35',18);   insert into tb_menu(id, title, parent) values(36, '二级菜单36',19);   insert into tb_menu(id, title, parent) values(37, '二级菜单37',20);      --三级菜单   insert into tb_menu(id, title, parent) values(38, '三级菜单38',21);   insert into tb_menu(id, title, parent) values(39, '三级菜单39',22);   insert into tb_menu(id, title, parent) values(40, '三级菜单40',23);   insert into tb_menu(id, title, parent) values(41, '三级菜单41',24);   insert into tb_menu(id, title, parent) values(42, '三级菜单42',25);   insert into tb_menu(id, title, parent) values(43, '三级菜单43',26);   insert into tb_menu(id, title, parent) values(44, '三级菜单44',27);   insert into tb_menu(id, title, parent) values(45, '三级菜单45',28);   insert into tb_menu(id, title, parent) values(46, '三级菜单46',28);   insert into tb_menu(id, title, parent) values(47, '三级菜单47',29);   insert into tb_menu(id, title, parent) values(48, '三级菜单48',30);   insert into tb_menu(id, title, parent) values(49, '三级菜单49',31);   insert into tb_menu(id, title, parent) values(50, '三级菜单50',31);   commit; 

2.查找所有上级节点

  --查询树状结构某节点(44)的上级所有根节点      with cte_parent(id,title,parent)      as      (        --起始条件        select id,title,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

  --查询树状结构某节点下的所有子节点(      with cte_child(id,title,parent,level)      as      (        --起始条件        select id,title,parent,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.title,a.parent,b.level+1        from tb_menu a        inner join         cte_child b        on ( a.parent=b.id)       )      select * from cte_child; 

以上这篇sqlserver实现树形结构递归查询(无限极分类)的方法就是小编分享给大家的全部内容了,希望能给大家一个参考,也希望大家多多支持沃谷博客。

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