有关数据库SQL递归查询在不同数据库中的实现方法

本文给大家介绍有关数据库SQL递归查询在不同数据库中的实现方法，具体内容请看下文。

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

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

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

//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

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 = '$';  SET sTempChd =cast(rootId as CHAR);    IF direction=1 THEN  WHILE sTempChd is not null DO    SET sTemp = concat(sTemp,',',sTempChd);    SELECT group_concat(id) INTO sTempChd FROM Tree where FIND_IN_SET(ParentId,sTempChd)>0;  END WHILE;  ELSEIF direction=2 THEN  WHILE sTempChd is not null DO    SET sTemp = concat(sTemp,',',sTempChd);    SELECT group_concat(ParentId) INTO sTempChd FROM Tree where FIND_IN_SET(Id,sTempChd)>0;  END WHILE;  END IF;RETURN sTemp;END

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