如何查询对象数组中的正则表达式并将结果切片到Mongodb？

Question

我有这样的文件..

"auction_list": [
    {
        "auction_id": 11368494,
        "domain": "51love.cn",
        "utf_name": "51love.cn",
        "is_idn": false,
        "auction_type": "backorder",
        "currency": "USD",
        "current_bid_price": "36.00",
        "bids": 25,
        "bidders": 4,
        "time_left": "4 days, 5 hours",
        "start_time": "2021/06/15 14:30 PST",
        "start_time_stamp": 1623792604841,
        "end_time": "2021/06/22 03:02 PST",
        "end_time_stamp": 1624356147000,
        "estibot_appraisal": "[=11=].00"
    },
    {
        "auction_id": 11381539,
        "domain": "meiguihualove.cn",
        "utf_name": "meiguihua.cn",
        "is_idn": false,
        "auction_type": "backorder",
        "currency": "USD",
        "current_bid_price": "15.99",
        "bids": 5,
        "bidders": 4,
        "time_left": "5 days, 5 hours",
        "start_time": "2021/06/16 14:30 PST",
        "start_time_stamp": 1623879010264,
        "end_time": "2021/06/23 03:02 PST",
        "end_time_stamp": 1624442573000,
        "estibot_appraisal": "[=11=].00"
    },
    {
        "auction_id": 11273186,
        "domain": "surpass.cn",
        "utf_name": "surpass.cn",
        "is_idn": false,
        "auction_type": "backorder",
        "currency": "USD",
        "current_bid_price": "14.99",
        "bids": 4,
        "bidders": 4,
        "time_left": "1 day, 5 hours",
        "start_time": "2021/06/09 14:30 PST",
        "start_time_stamp": 1623274205156,
        "end_time": "2021/06/19 03:02 PST",
        "end_time_stamp": 1624096958000,
        "estibot_appraisal": ".00"
    }

我在那个数组中总共有 30000 个对象。如果域词包含 love （使用正则表达式），我想搜索该域。并想将结果从第 1 项切片到第 50 项，如果找到，则将它们切片到第 50 到 100 项？

我试过了 ExpiredDomains.find({auction_list:{$elemMatch:{domain:'/love/'}}}) 和 ExpiredDomains.find({auction_list:{$elemMatch:{domain:{$regex: 'love'}}})

但这return没什么。我怎样才能做到这一点？我正在使用节点 js。提前致谢

Answer 1

以下聚合可以使用正则表达式过滤所有记录。

db.collection.aggregate([
  {
    "$project": {
      "auction_list": {
        "$filter": {
          "input": "$auction_list",
          "as": "list",
          cond: {
            "$regexMatch": {
              "input": "$$list.domain",
              "regex": /love/
            }
          }
        }
      }
    }
  },
  {
    "$unwind": "$auction_list"
  },
  {
    "$skip": 0
  },
  {
    "$limit": 50
  }
])

编辑：用于限制和跳过。

分配两个不同的变量：

const a = 0;
const b = 50;

//And use it like
  {
    "$skip": a
  },
  {
    "$limit": b
  }

并动态更改它们。跳过将忽略第一个 x 记录。如果你给 skip = 50 limit = 100 你将获得第二个 50 条记录。

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