如何使用 SQL 查询像父子一样显示层次结构行

我在我的应用程序中使用博客评论，其中我将每个评论行插入一个表中，这样如果其中任何一个评论对单击的特定评论进行回复commentid我插入为replyid在新行中。

下面是屏幕截图：

在这里你可以看到commentid24 和 26 有replycommentid23. 我需要一个查询来显示 23 之后的 24 和 26。因为 23 是 24 和 26 的父级。

以下是表布局和示例数据的设置脚本：

USE [myDB]
GO
/****** Object:  Table [dbo].[Blog_CommentDetails]    Script Date: 11/12/2016 6:36:04 PM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Blog_CommentDetails](
    [CommentID] [int] IDENTITY(1,1) NOT NULL,
    [CommentUserName] [nvarchar](200) NOT NULL,
    [CommentText] [nvarchar](max) NULL,
    [CommentApprovedByUserID] [int] NULL,
    [CommentPostDocumentID] [int] NOT NULL,
    [CommentDate] [datetime] NULL DEFAULT (getdate()),
    [HtmlComment] [nvarchar](max) NULL,
    [CommentIsSpam] [bit] NULL CONSTRAINT [DEFAULT_Blog_MainComment_CommentIsSpam]  DEFAULT ((0)),
    [CommentIsApproved] [bit] NULL CONSTRAINT [DEFAULT_Blog_MainComment_CommentIsApproved]  DEFAULT ((0)),
    [CommentEmail] [nvarchar](250) NULL,
    [CommentInfo] [nvarchar](max) NULL,
    [ReplyCommentID] [int] NULL
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

GO
SET IDENTITY_INSERT [dbo].[Blog_CommentDetails] ON 

GO
INSERT [dbo].[Blog_CommentDetails] ([CommentID], [CommentUserName], [CommentText], [CommentApprovedByUserID], [CommentPostDocumentID], [CommentDate], [HtmlComment], [CommentIsSpam], [CommentIsApproved], [CommentEmail], [CommentInfo], [ReplyCommentID]) VALUES (22, N'Vikash', N'This is main comment', NULL, 1, CAST(N'2016-11-12 17:36:25.637' AS DateTime), N'<div class="main-comment-section"><div class="row"><div class="col-xs-12"><div class="post-comment-section"><p id="pCommentorName"><span id="sCommentorName" class="blogcommentname">Vikash</span><span id="sBlogPostedDate">Nov12,2016 5:35PM</span></p><p class="comment-detail" id="pBlogCommentDetails">This is main comment</p><div class="comment-reply"><ul><li><img src="assets/svg/components/blog-detail/icon_reply.svg" alt="Reply comment icon"><a class="joinus-link" id="btnComment" href="#" target="_self">::blogdetailsReply</a></li></ul></div></div></div></div></div>', 0, 1, N'[email protected] /cdn-cgi/l/email-protection', NULL, NULL)
GO
INSERT [dbo].[Blog_CommentDetails] ([CommentID], [CommentUserName], [CommentText], [CommentApprovedByUserID], [CommentPostDocumentID], [CommentDate], [HtmlComment], [CommentIsSpam], [CommentIsApproved], [CommentEmail], [CommentInfo], [ReplyCommentID]) VALUES (23, N'Megha k', N'This is reply comment', NULL, 1, CAST(N'2016-11-12 17:39:04.250' AS DateTime), N'<div class="reply-comment-section"><div class="row"><div class="col-xs-12"><div class="post-comment-section"><p id="pBlogReplyCommentorName"><span id="sReplyCommentorName" class="blogcommentname">Megha k</span><span id="sBlogReplyCommentDate">Nov12,2016 5:38PM</span></p><p class="comment-detail" id="pBlogReplyCommentDetails">This is reply comment</p><div class="comment-reply"><ul><li><img class="contributors-list" src="assets/svg/components/blog-detail/icon_reply.svg" alt="Reply comment icon"><a class="joinus-link" id="btnCommentReply" href="#" target="_self">::blogdetailsReply</a></li></ul></div></div></div></div></div>', 0, 1, N'[email protected] /cdn-cgi/l/email-protection', NULL, NULL)
GO
INSERT [dbo].[Blog_CommentDetails] ([CommentID], [CommentUserName], [CommentText], [CommentApprovedByUserID], [CommentPostDocumentID], [CommentDate], [HtmlComment], [CommentIsSpam], [CommentIsApproved], [CommentEmail], [CommentInfo], [ReplyCommentID]) VALUES (24, N'Siddappa H', N'This is reply text.', NULL, 1, CAST(N'2016-11-12 17:39:58.847' AS DateTime), N'<div class="main-comment-section"><div class="row"><div class="col-xs-12"><div class="post-comment-section"><p id="pCommentorName"><span id="sCommentorName" class="blogcommentname">Siddappa H</span><span id="sBlogPostedDate">Nov12,2016 5:39PM</span></p><p class="comment-detail" id="pBlogCommentDetails">This is reply text.</p><div class="comment-reply"><ul><li><img src="assets/svg/components/blog-detail/icon_reply.svg" alt="Reply comment icon"><a class="joinus-link" id="btnComment" href="#" target="_self">::blogdetailsReply</a></li></ul></div></div></div></div></div>', 0, 1, N'[email protected] /cdn-cgi/l/email-protection', NULL, 23)
GO
INSERT [dbo].[Blog_CommentDetails] ([CommentID], [CommentUserName], [CommentText], [CommentApprovedByUserID], [CommentPostDocumentID], [CommentDate], [HtmlComment], [CommentIsSpam], [CommentIsApproved], [CommentEmail], [CommentInfo], [ReplyCommentID]) VALUES (25, N'Suresh P', N'This is reply comment', NULL, 1, CAST(N'2016-11-12 17:40:44.470' AS DateTime), N'<div class="reply-comment-section"><div class="row"><div class="col-xs-12"><div class="post-comment-section"><p id="pBlogReplyCommentorName"><span id="sReplyCommentorName" class="blogcommentname">Suresh P</span><span id="sBlogReplyCommentDate">Nov12,2016 5:40PM</span></p><p class="comment-detail" id="pBlogReplyCommentDetails">This is reply comment</p><div class="comment-reply"><ul><li><img class="contributors-list" src="assets/svg/components/blog-detail/icon_reply.svg" alt="Reply comment icon"><a class="joinus-link" id="btnCommentReply" href="#" target="_self">::blogdetailsReply</a></li></ul></div></div></div></div></div>', 0, 1, N'[email protected] /cdn-cgi/l/email-protection', NULL, NULL)
GO
INSERT [dbo].[Blog_CommentDetails] ([CommentID], [CommentUserName], [CommentText], [CommentApprovedByUserID], [CommentPostDocumentID], [CommentDate], [HtmlComment], [CommentIsSpam], [CommentIsApproved], [CommentEmail], [CommentInfo], [ReplyCommentID]) VALUES (26, N'Vikash', N'This is reply text', NULL, 1, CAST(N'2016-11-12 17:41:44.673' AS DateTime), N'<div class="reply-comment-section"><div class="row"><div class="col-xs-12"><div class="post-comment-section"><p id="pBlogReplyCommentorName"><span id="sReplyCommentorName" class="blogcommentname">Vikash</span><span id="sBlogReplyCommentDate">Nov12,2016 5:40PM</span></p><p class="comment-detail" id="pBlogReplyCommentDetails">This is reply text</p><div class="comment-reply"><ul><li><img class="contributors-list" src="assets/svg/components/blog-detail/icon_reply.svg" alt="Reply comment icon"><a class="joinus-link" id="btnCommentReply" href="#" target="_self">::blogdetailsReply</a></li></ul></div></div></div></div></div>', 0, 1, N'[email protected] /cdn-cgi/l/email-protection', NULL, 23)
GO
SET IDENTITY_INSERT [dbo].[Blog_CommentDetails] OFF
GO

欢迎所有建议！

我还在下面添加了三个插入查询：

Valex，请将此查询插入“INSERT [dbo].[Blog_CommentDetails] ([CommentID], [CommentUserName], [CommentText], [CommentApprovedByUserID], [CommentPostDocumentID], [CommentDate], [HtmlComment], [ CommentIsSpam]、[CommentIsApproved]、[CommentEmail]、[CommentInfo]、[ReplyCommentID]、[IsRejected]) 值 (58、N'Vicky'、N'Test'、0、1、CAST(N'2016-12-02) 11:51:07.270' AS DateTime), N'VickyDec2,2016 11:47AM

如果您想要完整的层次结构，甚至是其中的一部分，请按照正确的顺序

编辑 - 删除 2008 年的 Concat()

Declare @Top  int = 23 --null             --<<  Sets top of Hier Try 23
Declare @Nest varchar(25) ='|-----'  --<<  Optional: Added for readability

;with cteP as (
      Select Seq  = cast(1000+Row_Number() over (Order by CommentID) as varchar(500))
            ,CommentID
            ,ReplyCommentID
            ,Lvl=1
      From   [dbo].[Blog_CommentDetails]
      Where  IsNull(@Top,-1) = case when @Top is null then isnull(ReplyCommentID,-1) else CommentID end
      Union  All
      Select Seq  = cast(p.Seq+'.'+cast(1000+Row_Number() over (Order by r.CommentID) as varchar(25)) as varchar(500))
            ,r.CommentID
            ,r.ReplyCommentID
            ,p.Lvl+1
      From   [dbo].[Blog_CommentDetails] r 
      Join   cteP p on r.ReplyCommentID = p.CommentID)
     ,cteR1 as (Select *,R1=Row_Number() over (Order By Seq) From cteP)
     ,cteR2 as (Select A.Seq,A.CommentID,R2=Max(B.R1) From cteR1 A Join cteR1 B on (B.Seq like A.Seq+'%') Group By A.Seq,A.CommentID )
Select A.R1  
      ,B.R2
      ,A.CommentID
      ,A.ReplyCommentID
      ,A.Lvl
      ,CommentText = Replicate(@Nest,A.Lvl-1) + C.CommentText
      -- Include any other fields from [dbo].[Blog_CommentDetails] alias C
 From cteR1 A 
 Join cteR2 B on A.CommentID=B.CommentID
 Join [dbo].[Blog_CommentDetails] C on A.CommentID=C.CommentID
 Order By A.R1

Returns

如果 @Top 设置为 23（例如），则返回将为

我应该补充一点，cteR2 不是必需的，但它确实表明范围和/或父级或叶级。