(1)CREATE可以创建相同节点，merge若节点已存在，则不会重新添加。
CREATE (gp1:GoogleProfile1 {Id: 201401, Name:"Apple"})
CREATE (gp1:GoogleProfile1 {Id: 201401, Name:"Apple"})
MATCH (gp1:GoogleProfile1) RETURN gp1.Id,gp1.Name
MERGE (gp2:GoogleProfile2{ Id: 201402,Name:"Nokia"})
MERGE (gp2:GoogleProfile2{ Id: 201402,Name:"Nokia"})
MATCH (gp2:GoogleProfile2) RETURN gp2.Id,gp2.Name
（2）必须是节点的属性完全相同，否则，仍然创建新的节点。
MERGE (gp2:GoogleProfile2{ Id: 201402,Name:"Nokia",born:1989})
MATCH (gp2:GoogleProfile2) RETURN gp2.Id,gp2.Name,gp2.born
(3)节点不存在，则create set执行，match set不执行
merge(cc:Creditcard{name:"qiao"})on create set cc.time=3 on match set cc.year=2018 return cc.name,cc.time,cc.year
（4）节点存在，match set执行，create set不执行
create(into:Intopiece{name:"qiao"})return into
merge(into:Intopiece{name:"qiao"})on create set into.time=3 on match set into.year=2018 return into.name,into.time,into.year
