SQL Server 樹形表非循環遞歸查詢的實例詳解

2020-07-25 12:43:58

字體：大中小

來源：轉載

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很多人可能想要查詢整個樹形表關聯的內容都會通過循環遞歸來查...事實上在微軟在SQL2005或以上版本就能用別的語法進行查詢，下面是示例。

--通過子節點查詢父節點WITH TREE AS( SELECT * FROM Areas WHERE id = 6 -- 要查詢的子 id UNION ALL SELECT Areas.* FROM Areas, TREE WHERE TREE.PId = Areas.Id) SELECT Area FROM TREE--通過父節點查詢子節點WITH TREE AS( SELECT * FROM Areas WHERE id = 7 -- 要查詢的子 id UNION ALL SELECT Areas.* FROM Areas, TREE WHERE TREE.Id = Areas.PId) SELECT Area FROM TREE

通過子節點查詢父節點查詢結果為：

修改代碼為

--通過子節點查詢父節點declare @area varchar(8000);WITH TREE AS( SELECT * FROM Areas WHERE id = 6 -- 要查詢的子 id UNION ALL SELECT Areas.* FROM Areas, TREE WHERE TREE.PId = Areas.Id)select @area=isnull(@area,'')+Area from Tree order by id select Area= @area

則結果為：中國北京市豐臺區

根據以上可以將這段代碼封裝為一個存儲過程

-----存儲過程，遞歸獲取樹形地區表字符串if exists (select * from sysobjects where name='SP_GetAreaStr')drop proc SP_GetAreaStrgocreate procedure SP_GetAreaStr @id intasdeclare @area varchar(8000)beginWITH TREE AS( SELECT * FROM Areas WHERE id = @id -- 要查詢的子 id UNION ALL SELECT Areas.* FROM Areas, TREE WHERE TREE.PId = Areas.Id)select @area=isnull(@area,'')+Area from Tree order by id select Area= @areaend go--exec sp_helptext 'SP_GetAreaStr'--goexec SP_GetAreaStr 28go

查詢結果：中國安徽省宿州市靈璧縣

所用表結構：