arangodb - AQL - 在 ArangoDB 中查找具有非唯一属性的文档

Question

假设我有以下文件:

{"_key": "1", "name": "George Washington"}
{"_key": "2", "name": "George Washington"}
{"_key": "3", "name": "John Adams"}
{"_key": "4", "name": "Thomas Jefferson"}
{"_key": "5", "name": "George Washington"}
{"_key": "6", "name": "Thomas Jefferson"}

我想编写一个 AQL 语句来返回按名称分组的文档的键，但前提是该名称不止一次出现。

所以我想要的输出是:

[["1", "2", "5"], ["4", "6"]] 

到目前为止我想出了

FOR doc IN documents
    LET key = doc._key
    COLLECT name = doc.name INTO groups KEEP key
    RETURN (FOR g IN groups RETURN g["key"])

返回:

[["1", "2", "5"], ["3"], ["4", "6"]]

如何修改 AQL 命令以仅获取包含两个或更多条目的数组？

Answer 1

另一种可能性(可能更有效一点，因为不涉及子查询):

FOR doc IN documents
  LET key = doc._key     
  COLLECT name = doc.name INTO groups KEEP key 
  LET keys = groups[*].key 
  FILTER LENGTH(keys) > 1 
  RETURN keys