你的位置:首页 > 数据库

[数据库]关于SQL递归查询在不同数据库中的实现方法


比如表结构数据如下:

Table:Tree

ID Name ParentId

1 一级  0

2  二级  1

3  三级  2

4 四级  3

 

SQL SERVER 2005查询方法:

//上查with tmpTreeas(	select * from Tree where Id=2	union all	select p.* from tmpTree inner join Tree p on p.Id=tmpTree.ParentId)select * from tmpTree//下查with tmpTreeas(	select * from Tree where Id=2	union all	select s.* from tmpTree inner join Tree s on s.ParentId=tmpTree.Id)select * from tmpTree

SQL SERVER 2008及以后版本,还可用如下方法:

增加一列TID,类型设为:hierarchyid(这个是CLR类型,表示层级),且取消ParentId字段,变成如下:(表名为:Tree2)

TId    Id    Name

0x      1     一级
0x58     2    二级
0x5B40   3   三级
0x5B5E   4   四级

查询方法:

SELECT *,TId.GetLevel() as [level] FROM Tree2 --获取所有层级DECLARE @ParentTree hierarchyidSELECT @ParentTree=TId FROM Tree2 WHERE Id=2SELECT *,TId.GetLevel()AS [level] FROM Tree2 WHERE TId.IsDescendantOf(@ParentTree)=1 --获取指定的节点所有下级DECLARE @ChildTree hierarchyidSELECT @ChildTree=TId FROM Tree2 WHERE Id=3SELECT *,TId.GetLevel()AS [level] FROM Tree2 WHERE @ChildTree.IsDescendantOf(TId)=1 --获取指定的节点所有上级

可参见相关文章:http://blog.csdn.net/szstephenzhou/article/details/8277667

ORACLE中的查询方法:

SELECT *FROM TreeSTART WITH Id=2CONNECT BY PRIOR ID=ParentId --下查SELECT *FROM TreeSTART WITH Id=2CONNECT BY ID= PRIOR ParentId --上查

可参见相关文章:http://blog.csdn.net/super_marioli/article/details/6253639

MYSQL 中的查询方法:

//定义一个依据ID查询所有父ID为这个指定的ID的字符串列表,以逗号分隔CREATE DEFINER=`root`@`localhost` FUNCTION `getChildLst`(rootId int,direction int) RETURNS varchar(1000) CHARSET utf8BEGIN DECLARE sTemp VARCHAR(5000);  DECLARE sTempChd VARCHAR(1000);  SET sTemp = '$';  IF direction=1 THEN	 SET sTempChd =cast(rootId as CHAR);  ELSEIF direction=2 THEN	 SELECT cast(ParentId as CHAR) into sTempChd FROM Tree WHERE Id=rootId;  END IF;  WHILE sTempChd is not null DO		SET sTemp = concat(sTemp,',',sTempChd);		SELECT group_concat(id) INTO sTempChd FROM Tree where (direction=1 and FIND_IN_SET(ParentId,sTempChd)>0)		or (direction=2 and FIND_IN_SET(Id,sTempChd)>0);  END WHILE;RETURN sTemp;END//查询方法:select * from tree where find_in_set(id,getChildLst(1,1));--下查select * from tree where find_in_set(id,getChildLst(1,2));--上查

可参见相关文章:http://blog.csdn.net/jackiehome/article/details/6803978

说明:以上知识点均来源于网上,我这里只是做一个合计总结。