neo4j - 常用sql

查询结点

1、查询表所有节点

match (n:table_node) return count(n); 

2、查询去重后节点

match (n:table_node) return count(distinct n.table_name);

3、查看重复的id节点

match (n:table_node), (m:table_node) where n.table_name = m.table_name and id(n) <> id(m) return n,id(n);

查询下级节点

1、查询当前-下级节点

match (a)-->(b) where a.name = 'name' return a,b

2、查询当前节点往下多少级的节点

# 备注：r*..3  是要显示的级数
match (a)-[r*..3]->(b) where a.name = 'name' return a,b

查询节点的入度与出度

备注：可以用来分析节点被引用的频次等应用分析场景，辅助模型或架构升级重构

1、查询某个节点的入度与出度

MATCH (n:TableNode {name:"yz_datawarehouse_pg.ods_fpf_rfid_bind_record"})
WITH count{(n)-[]->()} as out,
     count{(n)<-[]-()} as in,
     n
RETURN  n,out,in

2、查询所有节点入度与出度

match (n:TableNode)
with n,
	count{(n)-[]->()} as out,
    count{(n)<-[]-()} as in
return n.name, out,in
order by n.name desc ;

3、查询入度与出度 为0 的节点

match (n:TableNode)
with n,
	count{(n)-[]->()} as out,
    count{(n)<-[]-()} as in
where in = 0 and out = 0
return n.name, out,in
order by n.name desc ;

删除结点

1、删除所有结点

match (n:table_node) delete n;

2、删除重复节点中的其中一个

MATCH (b:TableNode)
WITH b.name AS name, COLLECT(b) AS branches
WHERE SIZE(branches) > 1
FOREACH (n IN TAIL(branches) | DETACH DELETE n);