在MongoDB中检索某个月份和年份的JSON文档

用最简单的话说，你可以拥有这样的东西

db.collection("expenses").find({
  "users.username": "desired_username",
  $expr: {
    $and: [
      { $eq: [{ $year: "$date" }, 2020] },
      { $eq: [{ $month: "$date" }, 9] }
    ]
  }
})

playground个

或者，如果您想要更多花哨，您可以使用类似于日期到字符串的格式(need mongo 7表示使用%B并获得月份名称)

db.collection("expenses").find({
  "users.username": "desired_username",
  $expr: {
      { $eq: [{ $dateToString: { format: "%B, %Y", date: "$date" } }, "september, 2020"] }  
  }
})

这将不会在MongoPlatform上运行，因为它运行在较低的mongo版本上

或者一些可能在旧版本上运行的东西，如

db.collection("expenses").find({
  "users.username": "Giacomo",
  $expr: {
    $and: [
      { $eq: [{ $year: "$date" }, 2020] },
      {
        $eq: [
          {
            $arrayElemAt: [
              ["", "january", "february", "march", "april", "may", "june", "july", "august", "september", "october", "november", "december"],
              { $month: "$date" }
            ]
          },
          "september"
        ]
      }
    ]
  }
})

playground个

好的，最后一个只是为了好玩，但我想这太多了，使得查询有时很难理解(这正是第二种方法所示的更长的版本)

db.collection("expenses").find({
  "users.username": "Giacomo",
  $expr: {
    $eq: [
      {
        $concat: [
          {
            $arrayElemAt: [
              ["", "january", "february", "march", "april", "may", "june", "july", "august", "september", "october", "november", "december"],
              { $month: "$date" }
            ]
          },
          ", ",
          { $toString: { $year: "$date" } }
        ]
      },
      "september, 2020"
    ]
  }
})

playground个