json数组列表与n1ql couchbase之间的双重连接答案

【问题标题】：double join between json array lists with n1ql couchbasejson数组列表与n1ql couchbase之间的双重连接
【发布时间】：2016-08-19 14:40:30
【问题描述】：

我有以下名为 User 的 json 条目。有一个 selectedItemList 列表，可让用户对项目负责。

"myproject": {
  "_class": "com.demo.model.entity.User",
  "active": true,
  "createDate": 1470826033000,
  "description": "",
  "firstname": "Tom",
  "selectedItemList": [
    "MTR44",
    "MTR55",
    "MTR66"
  ],
  "type": "user",
  "username": "tom"
}

以下 3 项将 itemId 保持为唯一值

    "myproject": {
  "_class": "com.demo.model.entity.Item",
  "deleted": false,
  "factor": 0,
  "itemId": "MTR66",
  "type": "item"
}

"myproject": {
  "_class": "com.demo.model.entity.Item",
  "deleted": false,
  "factor": 0,
  "itemId": "MTR55",
  "type": "item"
}

"myproject": {
  "_class": "com.demo.model.entity.Item",
  "deleted": false,
  "factor": 0,
  "itemId": "MTR44",
  "type": "item"
}

有以下命令将项目 ID 保存为列表

"myproject": {
    "_class": "com.demo.model.entity.Orders",
    "model": "DR-503",
    "deleted": false,
    "itemIdList": [
        "MTR66",
        "MTR55"
    ],
    "type": "order"
}

"myproject": {
    "_class": "com.demo.model.entity.Orders",
    "model": "DR-504",
    "deleted": false,
    "itemIdList": [
        "MTR44"
    ],
    "type": "order"
}

我的问题是：我尝试获取负责用户“tom”下的项目订单列表。我的方式是：通过加入从订单中获取商品。但我无法将它与用户 tom 的 selectedItemList 和 itemId 加入（因为它不是一个对象，它是一个 json 数组）。

SELECT META(myproject).id as _ID, META(myproject).cas as _CAS, myproject.*  
FROM myproject
LEFT JOIN myproject item ON KEYS ARRAY itemId FOR itemId IN myproject.itemIdList 
LEFT JOIN ........

所以，我在第二次加入后无法写作，我对此一无所知。

【问题讨论】：

标签： json join couchbase n1ql nosql

【解决方案1】：

试试这个：

create index idxorderlist on myproject(itemIdList);

SELECT *
FROM  myproject u USE KEYS ["tom"]
      LEFT OUTER JOIN myproject item ON KEYS u.selectedItemList
      LEFT OUTER JOIN myproject `order` ON KEY `order`.itemIdList FOR item
;

【讨论】：