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。

--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：

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 

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')

SQLServer 之 树查询

SQLServer 之树查询