[学问分享] LINQ TO SQL 实现无限递归查询_SQL

[知识分享] LINQ TO SQL 实现无限递归查询

见论坛内有网友提问类似的问题已经不止一次了，
现总结一下，希望能给以后再碰到此类问题的朋友一些帮助

--构造测试数据： 只作演示用CREATE TABLE [dbo].[Tim_LinqTable]([Id] int PRIMARY KEY IDENTITY(1,1) NOT NULL,[Name] [varchar](50) NOT NULL,[Parent] int NOT NULL,)GOINSERT INTO [Tim_LinqTable]  SELECT 'A',0 UNION ALLSELECT 'A1',1 UNION ALLSELECT 'A2',1 UNION ALLSELECT 'B1',2 UNION ALLSELECT 'B2',3 UNION ALLSELECT 'C1',4 UNION ALLSELECT 'C2',4 UNION ALLSELECT 'D1',5 UNION ALLSELECT 'D2',5 UNION ALLSELECT 'D3',5 GOWITH tempAS(SELECT * FROM [Tim_LinqTable]  WHERE Parent = 3UNION ALLSELECT m.* FROM [Tim_LinqTable]  AS mINNER JOIN temp AS child ON m.Parent = child.Id)SELECT * FROM tempGO--查询 Parent=3 的所有子数据结果如下:Id          Name                                               Parent----------- -------------------------------------------------- -----------5           B2                                                 38           D1                                                 59           D2                                                 510          D3                                                 5(4 row(s) affected)

//好，下边来看看用C#怎么实现上边的SQL语句吧：void Main(){	 var query=GetSonID(3);	 Console.WriteLine("Id\tName\tParent");	 query.ToList().ForEach(q=>Console.WriteLine("{0}\t{1}\t{2}",q.Id,q.Name,q.Parent));	 /*		Id       Name       Parent		5        B2         3		8        D1         5		9        D2         5	        10        D3         5	 */}public IEnumerable<Tim_LinqTable> GetSonID(int p_id){	var query = from c in this.Tim_LinqTables		   where c.Parent  == p_id		   select c;		 	return  query.ToList().Concat(query.ToList().SelectMany(t => GetSonID(t.Id)));              }

更多LINQ知识分享，请参考：
http://blog.csdn.net/q107770540