blocks|key|794854|text|我相信您的第一个查询几乎是正确的，唯一的一点是您对同一个节点A使用了不同的别名，这将强制表示a和a2是图中的不同节点，b和b2的别名相同|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|794855|试试这个|794856|match+(a:A)--(b:B)--(c:C)--(d:D)--(c2:C)--(b)--(a)
where+a.id+=+a2.id+and+b.id+=+b2.id
return+count(d)|code-block|syntax|javascript|794857|entityMap^0|U|1|1A|1|1C|2|1N|1|1P|2|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]|$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Z|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|10|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|N|$]]

I believe your first query is almost correct, the only bit is that you're using a different alias for the same node <code>A</code> which would enforce that <code>a</code> and <code>a2</code> are different nodes in the graph, same for <code>b</code> and <code>b2</code>
Try this one
<pre><code>match (a:A)--(b:B)--(c:C)--(d:D)--(c2:C)--(b)--(a)
where a.id = a2.id and b.id = b2.id
return count(d)
</code></pre>

blocks|key|676149|text|您的问题：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|676150|match+(a:A)--(b:B)--(c:C)--(d:D)--(c2:C)--(b2:B)--(a2:A)
where+a.id+=+a2.id+and+b.id+=+b2.id
return+count(d)

match+(a:A)--(b:B)
with+a,b+
match+(a)--(b)--(c:C)--(d:D)--(c2:C)--(b)--(a)
return+count(d)|code-block|syntax|javascript|676151|由于您的模式(c2:C)--(b2:B)--(a2:A)和(c2:C)--(b)--(a)中的最后匹配，所以没有返回匹配。原因是数据库中只有一个B和一个A节点。因此，当这些匹配发生时，neo4j尝试在a和b之间找到一条新路径，而不是从一开始就获取的路径。因为，在a和b之间只有一种关系，所以在此匹配中找不到路径。因此，你看不到火柴。要修复它，只需从末尾删除a，因为它是多余的，如下所示：|offset|length|style|CODE|676152|match+(a:A)--(b:B)--(c:C)--(d:D)--(c2:C)--(b)
return+count(d)|676153|由于笛卡尔产品的原因，上面返回的计数可能看起来不正确，要准确地计算，请使用以下命令：|676154|match+(a:A)--(b:B)--(c:C)--(d:D)--(c2:C)--(b)
return+count(DISTINCT+d)|676155|编辑|BOLD|676156|上面显示的图表只有一个B节点，链接到A。你的路径在最后失败的原因是(b)--(a)已经建立了，并且在b和a之间没有新的路径。我使用以下查询在空图上创建了多个链接到B节点的A节点：|676157|MERGE+(a:A{id:+1})
MERGE+(b:B{id:+1})
MERGE+(c:C{id:+1})
MERGE+(c1:C{id:+2})
MERGE+(c2:C{id:+3})
MERGE+(d:D{id:+1})
MERGE+(a)<-[:R]-(b)
MERGE+(c)-[:R]->(b)
MERGE+(c1)-[:R]->(b)
MERGE+(c2)-[:R]->(b)
MERGE+(c)-[:R]->(d)
MERGE+(c1)-[:R]->(d)
MERGE+(c2)-[:R]->(d)

//+This+is+a+separate+query.
CREATE+(b:B{id:+1})
WITH+b
MATCH+(c:C{id:+1})
MATCH+(c1:C{id:+2})
MATCH+(c2:C{id:+3})
MATCH+(a:A{id:+1})
MERGE+(b)-[:R]->(a)
MERGE+(c)-[:R]->(b)
MERGE+(c1)-[:R]->(b)
MERGE+(c2)-[:R]->(b)|676158|现在，匹配成功，并使用以下查询返回一个非零计数：|676159|match+(a:A)--(b:B)--(c:C)--(d:D)--(c2:C)--(b2:B)--(a2:A)
where+a.id+=+a2.id+and+b.id+=+b2.id
return+count(d)|676160|entityMap^0|0|0|6|M|T|G|20|1|24|1|4Y|1|0|0|0|0|0|2|0|B|1|I|1|29|1|2D|1|0|0|0|0^^$0|@$1|2|3|4|5|6|7|15|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|16|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|17|8|@$I|18|J|19|K|L]|$I|1A|J|1B|K|L]|$I|1C|J|1D|K|L]|$I|1E|J|1F|K|L]|$I|1G|J|1H|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|1I|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|1J|8|@]|9|@]|A|$]]|$1|Q|3|R|5|D|7|1K|8|@]|9|@]|A|$E|F]]|$1|S|3|T|5|6|7|1L|8|@$I|1M|J|1N|K|U]]|9|@]|A|$]]|$1|V|3|W|5|6|7|1O|8|@$I|1P|J|1Q|K|L]|$I|1R|J|1S|K|L]|$I|1T|J|1U|K|L]|$I|1V|J|1W|K|L]]|9|@]|A|$]]|$1|X|3|Y|5|D|7|1X|8|@]|9|@]|A|$E|F]]|$1|Z|3|10|5|6|7|1Y|8|@]|9|@]|A|$]]|$1|11|3|12|5|D|7|1Z|8|@]|9|@]|A|$E|F]]|$1|13|3|-4|5|6|7|20|8|@]|9|@]|A|$]]]|14|$]]

Your queries:
<pre><code>match (a:A)--(b:B)--(c:C)--(d:D)--(c2:C)--(b2:B)--(a2:A)
where a.id = a2.id and b.id = b2.id
return count(d)

match (a:A)--(b:B)
with a,b 
match (a)--(b)--(c:C)--(d:D)--(c2:C)--(b)--(a)
return count(d)
</code></pre>
are not returning matches due to the last matches in your pattern <code>(c2:C)--(b2:B)--(a2:A)</code> and <code>(c2:C)--(b)--(a)</code>. The reason being there are only 1 <code>B</code> and 1 <code>A</code> nodes in your database. So, when these matches occur neo4j tries to find a new path between a and b, other than the one it has fetched from the beginning. Since, there is only one relationship between a and b, no path is found for this match. Hence, you see no matches. To fix it, you can simply remove <code>a</code> from the end, since it's redundant, like this:
<pre><code>match (a:A)--(b:B)--(c:C)--(d:D)--(c2:C)--(b)
return count(d)
</code></pre>
The count returned above might seem incorrect due to the Cartesian product, for the exact count, use this:
<pre><code>match (a:A)--(b:B)--(c:C)--(d:D)--(c2:C)--(b)
return count(DISTINCT d)
</code></pre>
EDIT
The graph you showed above, has only one <code>B</code> node, linked to <code>A</code>. The reason your path fails at the end is that (b)--(a) is already established, and no new path between b and a is there. I created multiple <code>B</code> nodes linked to <code>A</code> nodes, on an empty graph, using the queries:
<pre><code>MERGE (a:A{id: 1})
MERGE (b:B{id: 1})
MERGE (c:C{id: 1})
MERGE (c1:C{id: 2})
MERGE (c2:C{id: 3})
MERGE (d:D{id: 1})
MERGE (a)&lt;-[:R]-(b)
MERGE (c)-[:R]-&gt;(b)
MERGE (c1)-[:R]-&gt;(b)
MERGE (c2)-[:R]-&gt;(b)
MERGE (c)-[:R]-&gt;(d)
MERGE (c1)-[:R]-&gt;(d)
MERGE (c2)-[:R]-&gt;(d)

// This is a separate query.
CREATE (b:B{id: 1})
WITH b
MATCH (c:C{id: 1})
MATCH (c1:C{id: 2})
MATCH (c2:C{id: 3})
MATCH (a:A{id: 1})
MERGE (b)-[:R]-&gt;(a)
MERGE (c)-[:R]-&gt;(b)
MERGE (c1)-[:R]-&gt;(b)
MERGE (c2)-[:R]-&gt;(b)
</code></pre>
Now, the match is successful and a non-zero count is returned, using the query:
<pre><code>match (a:A)--(b:B)--(c:C)--(d:D)--(c2:C)--(b2:B)--(a2:A)
where a.id = a2.id and b.id = b2.id
return count(d)
</code></pre>

I have a path like the one in the image shown
<a href="https://i.stack.imgur.com/K4Iit.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/K4Iit.png" alt="path" /></a>
When I do this match query, there is no match returned, which is strange:
<pre><code>match (a:A)--(b:B)--(c:C)--(d:D)--(c2:C)--(b2:B)--(a2:A)
where a.id = a2.id and b.id = b2.id
return count(d)
</code></pre>
This one is giving no match too:
<pre><code>match (a:A)--(b:B)
with a,b 
match (a)--(b)--(c:C)--(d:D)--(c2:C)--(b)--(a)
return count(d)
</code></pre>
But this one is giving the paths, if <code>C</code> type nodes have the property <code>B_id</code> which is the ID of their node <code>B</code> type attached to them:
<pre><code>match (c:C)--(d:D)--(c2:C)
where c.B_id = c2.B_id
return count(d)
</code></pre>
This seems strange to me.
Any ideas on why those matches are not working? 
Which would be the query to retrieve <code>count(d)</code>?

Neo4j Cypher : existing match path exists but no match is returned if first node is equal to last node

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我有一条类似于图片中的路径​​当我执行此匹配查询时，没有返回匹配，这很奇怪：match (a:A)--(b:B)--(c:C)--(d:D)--(c2:C)--(b2:B)--(a2:A)where a.id = a2.id and b.id = b2.idreturn count(d)这一次也无济于事：match (...

问Neo4j Cypher :现有匹配路径存在，但如果第一个节点与最后一个节点相等，则不返回匹配
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问Neo4j Cypher :现有匹配路径存在，但如果第一个节点与最后一个节点相等，则不返回匹配EN