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')