SqlServer与Linq 无限递归目录树且输出层级

ALTER VIEW [dbo].[view_TreeLevel]
AS
WITH cte
AS (
SELECT a.ModuleID ,
       a.Module_Name ,
       a.Module_Description ,
       a.Module_FatherID ,
       a.Module_Url ,
       a.Module_Order, 1 Level FROM TT_TreeView a WHERE a.Module_FatherID=0
UNION ALL 
SELECT b.ModuleID ,
       b.Module_Name ,
       b.Module_Description ,
       b.Module_FatherID ,
       b.Module_Url ,
       b.Module_Order, Level+1 FROM TT_TreeView b INNER JOIN cte c ON b.Module_FatherID = c.ModuleID
)
SELECT TOP 100 PERCENT * FROM cte ORDER BY Level

CREATE TABLE [dbo].[AreaTable](  
[Id] int PRIMARY KEY IDENTITY(1,1) NOT NULL,  
[Name] [varchar](50) NOT NULL,  
[Parent] int NOT NULL,  
)  
GO  
  
INSERT INTO [AreaTable]    
SELECT '中国',0 UNION ALL  
SELECT '广东',1 UNION ALL  
SELECT '湖南',1 UNION ALL  
SELECT '深圳',2 UNION ALL  
SELECT '长沙',3 UNION ALL  
SELECT '福田',4 UNION ALL  
SELECT '南山',4 UNION ALL  
SELECT '天心',5 UNION ALL  
SELECT '岳麓',5 UNION ALL  
SELECT '芙蓉',5 UNION ALL  
SELECT '蛇口',7 UNION ALL  
SELECT '科技园',7   
GO  

--查询全国  
WITH temp  
AS  
(  
SELECT *,1 Level FROM [AreaTable]  WHERE Parent = 1  --1全国  2广东
UNION ALL  
SELECT m.*,Level+1  FROM [AreaTable]  AS m  
INNER JOIN temp AS child ON m.Parent = child.Id  
)  
SELECT * FROM temp ORDER BY temp.Level

void Main()  
{  
	var query = GetChildren(2);  //Linq递归查询方法
	Console.WriteLine("Id	Name	Parent");
	query.ToList().ForEach(q => Console.WriteLine("{0}	{1}	{2}", q.Id, q.Name, q.Parent));
} 

private IEnumerable<AreaTable> GetChildren(int p_id)
{
	var query = RBAC.Dal.DataRootBase.Context.From<AreaTable>().Where(p => p.Parent == p_id);
	return query.ToList().Concat(query.ToList().SelectMany(t => GetChildren(t.Id)));
}


原文地址:https://www.cnblogs.com/smartsmile/p/6234019.html