SQLServer 之 树查询

一、SqlServer树查询

1、使用公用表表达式（CTE）

很多人可能想要查询整个树形表关联的内容都会通过循环递归来查...事实上在微软在SQL2005或以上版本就能用别的语法进行查询，下面是示例。

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--通过子节点查询父节点 With Tree As(     Select * From table     Where id = 6  -- 要查询的子 id     Union All     Select table.* From table, Tree     Where Tree.parent = table.id ) Select * From Tree;   --通过父节点查询子节点 With Tree As(     Select * From table     Where parent = 2  -- 要查询的父 id     Union All     Select table.* From table, Tree     Where table.parent = Tree.id ) Select * From Tree;

 2、自定义函数方式：

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Create Function dbo.GetSubtreeInfo ( @parentId AS nvarchar(20) ) Returns @treeinfo table (   FunctionId nvarchar(20) NOT NULL ,     FunctionName nvarchar(50) NOT NULL,     Url nvarchar(100),     ParentId nvarchar(20) NOT NULL,     OrderId nvarchar(20),     [levels] [int] NOT NULL ) As Begin <br> Declare @level As int Select @level = 0 Insert Into @treeinfo     Select FunctionId, FunctionName, Url, ParentId, OrderId, @level     From SystemFunction     Where ParentId  = @parentId While @@ROWCOUNT > 0 Begin   Set @level = @level + 1 Insert Into @treeinfo     Select E.FunctionId, E.FunctionName, E.Url, E.ParentId, E.OrderId, @level     From SystemFunction as E JOIN @treeinfo as T     On E.ParentId = T.FunctionId and T.levels = @level - 1   End Return End drop function dbo.GetSubtreeInfo select * from dbo.GetSubtreeInfo('F0000')