Question

该查询应按月份过滤结果，似乎运行良好。但是我也不知道如何添加年份过滤器。

db.collection.find({
  "$expr": {
    "$eq": [{ "$month": "$timestamp" }, 12]
  }
});

我试图提出类似的方法，但没有成功。

db.collection.find({
  "$expr": {
    "$and": [
      { "$eq": [{ "$month": "$timestamp" }, 12] }, 
      { "$eq": [{ "$year": "$timestamp" }, 2018] }
    ]
  }
});

如何正确执行此操作？

Answer 1

您可以使用aggregate代替find。

三步解决方案将非常有用：

$project的年和月字段以及文档本身，使用$$ROOT。由于$project仅输出指定的字段，因此我们也需要投影文档本身。
使用$match按年份和月份过滤。
$replaceRoot将原始文档放回顶层（将其展平）。

db.collection.aggregate([
  {
    "$project": {
      "year": { "$year": "$timestamp" },
      "month": { "$month": "$timestamp" },
      "document": "$$ROOT"
    }
  },
  {
    "$match": {
      "year": 2018,
      "month": 12
    }
  },
  {
    "$replaceRoot": { "newRoot": "$document" }
  }
])

Answer 2

我想使用查找而不是聚合。只需添加另一个> <HTTParty::Response:0x7ff207cd0270 parsed_response=[{"id"=>69359, "name"=>"Sunken Secrets"}, {"id"=>69530, "name"=>"Dai Senryaku VII: > Modern Military Tactics"}, {"id"=>81332, "name"=>"Stick Fighter II"}, > {"id"=>50649, "name"=>"Who Wants to be a Millionaire: 1st Edition"}, > {"id"=>22618, "name"=>"Battleground 7: Bull Run"}, {"id"=>104945, > "name"=>"Woodpunk"}, {"id"=>91579, "name"=>"Racing Live"}, > {"id"=>22636, "name"=>"Call of Duty: Black Ops - Annihilation"}, > {"id"=>88041, "name"=>"Highway Wars"}, {"id"=>31258, > "name"=>"Slymes"}, {"id"=>90512, "name"=>"Asian Riddles 4"}, > {"id"=>105842, "name"=>"Robots Vs Zombies: Transform To Race And > Fight"}, {"id"=>85450, "name"=>"Transformers Prime: The Game"}, > {"id"=>104748, "name"=>"Space station - build your own ISS"}, > {"id"=>111593, "name"=>"Oppai Puzzle"}, {"id"=>42610, > "name"=>"Hebereke's Popoon"}, {"id"=>105254, "name"=>"Codenames"}, > {"id"=>91756, "name"=>"Aban Hawkins & the 1000 SPIKES"}, {"id"=>2057, > "name"=>"Out Run 2019"}, {"id"=>93987, "name"=>"Pi Story"}], > @response=#<Net::HTTPOK 200 OK readbody=true>, > @headers={"date"=>["Wed, 25 Dec 2019 18:04:48 GMT"], > "content-type"=>["application/json;charset=utf-8"], > "content-length"=>["1259"], "connection"=>["close"], > "set-cookie"=>["__cfduid=de604d7fc295fb415e047830a8ce304281577297088; > expires=Fri, 24-Jan-20 18:04:48 GMT; path=/; domain=.igdb.com; > HttpOnly; SameSite=Lax"], "x-count"=>["124726"], "via"=>["1.1 vegur"], > "cf-cache-status"=>["DYNAMIC"], > "strict-transport-security"=>["max-age=15552000; preload"], > "x-content-type-options"=>["nosniff"], "expect-ct"=>["max-age=604800, > report-uri=\"https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct\""], "server"=>["cloudflare"], "cf-ray"=>["54acbd52ae077cb2-MUC"]}>即可为我工作。

$eq

MongoDB使用多个eq查找expr

2 个答案: