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sqlite树型结构查询

时间:2021-07-01 10:21:17 帮助过:3人阅读

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

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