Sql查询tbl注释

Question

Comment:tbl

CommentId PK  
CommentEntry  
CommentDate  
Category  
CommentCommentId  
BlogEntryId FK


Insert into Comment(CommentId, CommentEntry, CommentDate, Category, CommentCommentId, BlogEntryId)
Values("1","I love shoes","10-3-2011","1","" ,"13"),
("2","I love shoes too","10-4-2011","1","1" ,"13"),
("3","There nice shoes in the mall","2","","13");

问题：对于给定博客条目的第一条评论，仅生成对该原始评论的任何进一步评论。应提示用户输入博客条目的唯一标识符。

ANS 假设：

("1","I love shoes","10-3-2011","1","" ,"13"),
("2","I love shoes too","10-4-2011","1","1" ,"13")

请帮助处理 sql

我想做一个自连接来接受 [BlogEntryId] 和产品第 1 条评论 'CommentCommentId=""' 以及第 1 条评论的所有评论。

请帮助sql:)

Answer 1

只需在原始查询中添加一点：

SELECT * 
FROM Comment 
WHERE BlogEntryId = [?Blog Entry] 
AND (
    CommentId = (SELECT CommentId FROM Comment WHERE CommentDate = (SELECT min(CommentDate) from Comment))
    OR
    CommentCommentId = (SELECT CommentId FROM Comment WHERE CommentDate = (SELECT min(CommentDate) from Comment))
    )

Answer 2

我猜你想要这样的东西：

select * 
from comment c
join comment subc on c.commentcommentid = subc.commentid
where c.commentid = @inputID

这是一个自连接。

我认为作业问题的答案很简单：

select *
from comment
where commentcommentid = @inputid