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.Nam

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