在 SQL Server 中使用 FOR XML PATH 查询以获取分层数据的 XML 输出

2021-09-10 00:00:00 xml sql tsql sql-server for-xml

我有一个包含 NodeId、NodeName、ParentNodeId 列的表，我想使用 SQL 查询以 Xml 的形式输出整个表数据，如下所示.我认为 Sql server 中的 FOR XML PATH 模式可用于使用递归来实现这一点(我使用 SQL Server 2008)，但不确定如何.提前致谢

I have a table with columns NodeId, NodeName, ParentNodeId and I want to ouput entire table data in the form of Xml like the following using SQL query. I think FOR XML PATH mode in Sql server can be used to achieve this (I use SQL Server 2008) using recursion, but not sure how. Thanks in advance

<?xml version="1.0" encoding="utf-8" ?>
<Nodes>
  <Node Id="1" Name="node1">
    <Node Id="11" Name="node11">
      <Node Id="111" Name="node111" />
      <Node Id="112" Name="node112" />
    </Node>
  </Node>
  <Node Id="2" Name="node2">
    <Node Id="21" Name="node21">
      <Node Id="211" Name="node211" />
      <Node Id="212" Name="node212" />
    </Node>
  </Node>
</Nodes>

推荐答案

我使用存储过程和递归函数解决了这个问题.代码如下所示.(实际上我希望它生成一个菜单xml，因此显示了菜单的代码.

I solved it using a stored procedure and a recursive function. code shown below. (actually I wanted this to generate a menu xml, so the code is shown for the menu.

    CREATE PROCEDURE [dbo].[usp_GetMenu]
    AS
    BEGIN
        SET NOCOUNT ON;

        SELECT  dbo.fnGetMenuItems(MenuId)
        FROM    dbo.Menu
        WHERE   ParentMenuId IS NULL
        FOR XML PATH('MenuItems')
    END
    GO

CREATE FUNCTION [dbo].[fnGetMenuItems]
(
    @MenuId int
)
RETURNS XML
WITH RETURNS NULL ON NULL INPUT
AS
BEGIN

    RETURN 
    (
        SELECT  MenuId AS "@Id"
                , [Name] AS "@Name"
                , [URL] AS "@URL"
                , [Key] AS "@Key"
                , [dbo].[fnGetMenuItems](MenuId)
        FROM    dbo.Menu
        WHERE   ParentMenuId = @MenuId
        FOR XML PATH('MenuItem'),TYPE
    )

END
GO

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