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sqlite树型结构查询

sqlite树型结构查询
 
表结构:tblCity(ID, ParentID, Name)
 
因为sqlite 没有row_number函数,也不能递归查询,所幸它有RowID 这个字段。只好采用这种 笨方法
 
1)
 
[sql] 
select ID,Name,1 as Level from tblCity where ParentID=0  
union all   
select a.ID,a.Name,c.RowID as Level from tblCity a   
inner join tblCity b on a.ParentID=b.ID  
inner join   
(  
      select ParentID from tblCity group by ParentID  
) c on a.ParentID=c.ParentID  
 
2)
[sql] 
select ID,Name,1 as Level from tblCity where ParentID=0  
union all   
select a.ID,a.Name,c.RowID as Level from tblCity a   
inner join tblCity b on a.ParentID=b.ID  
inner join   
(  
      select ParentID from tblCity group by ParentID  
) c on a.ParentID=c.ParentID  
 
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