子查询获取父addby字段

Question

我试图在我的表中创建一个名为 Owner 的字段，您可以在其中选择已添加的字段，其中 parentID 等于 PostID 到目前为止，它只打印出第一个字段，第二个字段始终为空。我对查询进行子查询。我正在尝试获取父 AdditionalBy 字段

SELECT Level, Sequence, PostID, AddedBy, Title, ParentID, Path_String,
   CASE WHEN ParentID IS NULL THEN
       AddedBy 
   ELSE
       (SELECT AddedBy FROM cte o WHERE o.PostID = ParentID)
   END AS Owner
FROM cte order by Sequence

我正在尝试计算与通过 ParentID 加入的 PostID 相关的所有帖子的数量，但我收到错误，所以当我对所有字段进行分组时，我仍然收到错误：- 错误如下

SELECT s.Level, s.Sequence, s.PostID, s.AddedBy,  
s.Title, s.ParentID, s.Path_String, 
Owner = COALESCE(o.AddedBy, s.AddedBy), COUNT(r.ParentID)
FROM cte AS s 
LEFT OUTER JOIN cte AS o 
ON s.ParentID = o.PostID 
RIGHT join cte AS r
on s.PostID = r.ParentID
ORDER BY s.Sequence; 

我收到以下错误：

Msg 8120, Level 16, State 1, Procedure sproc_GetPostsByThread, Line 34
Column 'cte.Level' is invalid in the select list because it is not
contained in either an aggregate function or the GROUP BY clause.

PostID、ParentID、AddedBy、Title、Path_String：- PostID 为 IdentityColumn Path_String 的格式为 1/、1/1/、1/1/2，ParentID 为整数

    Level       Sequence                    PostID      AddedBy    Title     ParentID    Path_String  Owner    Count                                          

---

1     00000003                          3           kirkdm     test      NULL        3/           kirkdm   1
2     0000000300000005                  5           MikeDM     re: test  3           3/5/         kirkdm   2
3     000000030000000500000008          8           Joelene    re: test  5           3/5/8/       MikeDM   2
3     000000030000000500000009          9           kirkdm     re: test  5           3/5/9/       MikeDM   1
4     00000003000000050000000900000010  10          Crushanin  re: test  9           3/5/9/10/    kirkdm   1

应该是这个

Level       Sequence                                     PostID      AddedBy      Title     ParentID    Path_String     Owner     Count column here 

---

1           00000003                                     3           kirkdm       test      NULL        3/              kirkdm
2           0000000300000005                             5           MikeDM       re: test  3           3/5/            kirkdm
3           000000030000000500000008                     8           Joelene      re: test  5           3/5/8/          MikeDM
4           00000003000000050000000800000014             14          Christian    re: test  8           3/5/8/14/       Joelene
4           00000003000000050000000800000015             15          Zeke         re: test  8           3/5/8/15/       Joelene
3           000000030000000500000009                     9           kirkdm       re: test  5           3/5/9/          MikeDM
4           00000003000000050000000900000010             10          Crushanin    re: test  9           3/5/9/10/       kirkdm
5           0000000300000005000000090000001000000011     11          Tim          re: test  10          3/5/9/10/11/    Crushanin

Answer 1

SELECT s.Level, s.Sequence, s.PostID, s.AddedBy, 
   s.Title, s.ParentID, s.Path_String,
   Owner = COALESCE(o.AddedBy, s.AddedBy)
FROM cte AS s
LEFT OUTER JOIN cte AS o
ON s.ParentID = o.PostID
ORDER BY s.Sequence;