Question

我正在尝试了解Cypher中以下查询的输出。

start n=node:node_auto_index(name="root_node")
match n-[:SC]->c, b<-[:CB]-c-[:CB]->b1
where (b.days_in_number - b1.days_in_number <= 7) AND (b.days_in_number > b1.days_in_number)
and c.name = "C16659"
with  distinct n,c, b, b1
match  n-[:SC]->c-[:CB]->b-[:CT]->i1, n-[:SC]->c-[:CB]->b1-[:CT]->i2 
with b.name as bname,b1.name as b1name,i1.name as i1name,i2.name as i2name
return  bname,b1name,i1name,i2name
order by bname,b1name,i1name,i2name;

返回3680行

start n=node:node_auto_index(name="root_node") 
match n-[:SC]->c, b<-[:CB]-c-[:CB]->b1
where (b.days_in_number - b1.days_in_number <= 7) AND (b.days_in_number > b1.days_in_number)
and c.name = "C16659"
with  distinct n,c, b, b1
match  b-[:CT]->i1, b1-[:CT]->i2 
with b.name as bname,b1.name as b1name,i1.name as i1name,i2.name as i2name
return  bname,b1name,i1name,i2name
order by bname,b1name,i1name,i2name;

返回184行

查询1似乎在做笛卡儿，但我无法理解为什么？有人可以解释一下吗？

c - [：CB] - ＆gt; b是1：n关系。

更新：

当我运行以下查询时，我得到了正确的184个结果：

start n=node:node_auto_index(name="root_node") 
match n-[:SC]->c, b<-[:CB]-c-[:CB]->b1
where (b.days_in_number - b1.days_in_number <= 7) AND (b.days_in_number > b1.days_in_number)
and c.name = "C16659"
with  distinct n,c, b, b1
match  c-[:CB]->b-[:CT]->i1, c-[:CB]->b1-[:CT]->i2 
with n.name as nname,c.name as cname, b.name as bname,b1.name as b1name,i1.name as i1name,i2.name as i2name
return  nname,cname,bname,b1name,i1name,i2name
order by nname,cname,bname,b1name,i1name,i2name;

这表明将n个引线引向笛卡儿。

n - [：SC] - ＆gt; c是1：1的关系。为什么会这样？

Answer 1

您是否确认n和c之间的关系真的很独特？也许看着路径会有所帮助。尝试

match p1=n-[:SC]->c-[:CB]->b-[:CT]->i1, p2=n-[:SC]->c-[:CB]->b1-[:CT]->i2
return p1,p2

查看其他结果之间的差异。

了解Cypher查询

1 个答案: