MongoDB的陣列文檔搜索

Question

這是一個很簡單的問題，我找遍了所有，但could'nt找到答案

我只有

{ 
"_id" : 1, 
    "name" : { 
     "first" : "John", 
     "last" : "Backus" 
    }, 
"awards" : [ 
     { 
      "award" : "W.W. McDowell Award", 
      **"year" : 1967,** 
      "by" : "IEEE Computer Society" 
     }, 
     { 
      "award" : "Draper Prize", 
      **"year" : 1967,** 
      "by" : "National Academy of Engineering" 
     }, 
     { 
      "award" : "National Medal of Science", 
      "year" : 1975, 
      "by" : "National Science Foundation" 
     } 
    ] 
}, 
{ 
"_id" : 2, 
    "name" : { 
     "first" : "John", 
     "last" : "McCarthy" 
    }, 
"awards" : [ 
     { 
      "award" : "Turing Award", 
      "year" : 1971, 
      "by" : "ACM" 
     }, 
     { 
      "award" : "Kyoto Prize", 
      **"year" : 1967,** 
      "by" : "Inamori Foundation" 
     }, 
     { 
      "award" : "National Medal of Science", 
      "year" : 1990, 
      "by" : "National Science Foundation" 
     } 
    ] 
}, 

所有我需要的是，一直是所有獎項在1967年贏得了！

，我試圖

，我只得到

"_id" : 1, 
"awards" : [ 
     { 
      "award" : "W.W. McDowell Award", 
      "year" : 1967, 
      "by" : "IEEE Computer Society" 
     }, 

], 

，但我需要在所有的文件，找到（在firsdt一個有兩個這樣totalyy 3樣

{ 
"_id" : 1, 
    "awards" : [ 
      { 
       "award" : "W.W. McDowell Award", 
       "year" : 1967, 
       "by" : "IEEE Computer Society" 
      }, 
      { 
       "award" : "Draper Prize", 
       **"year" : 1967,** 
       "by" : "National Academy of Engineering" 
      } 
    ] 
}, 
{ 
    "_id" : 2, 
    "award":[{ 
       "award" : "Kyoto Prize", 
       "year" : 1967, 
       "by" : "Inamori Foundation" 
      } 
    ] 
} 

我嘗試使用$all，但無法得到結果。我希望我的明確 是的，我正在使用BIOS的例子。 這一定很簡單，我正在做短暫的動作 請幫忙。

Answer 1

您必須使用aggregation framework，因爲$僅指第一個匹配項。在你的情況，以下可能的工作：

db.bios.aggregate([ 
    { $match : {"awards.year":1967} }, 
    { $unwind : "$awards"}, 
    { $match : {"awards.year" :1967} } 
]); 

屈服

{ 
     "_id" : 1, 
     "name" : { 
       "first" : "John", 
       "last" : "Backus" 
     }, 
     "awards" : { 
       "award" : "W.W. McDowell Award", 
       "year" : 1967, 
       "by" : "IEEE Computer Society" 
     } 
} 
{ 
     "_id" : 1, 
     "name" : { 
       "first" : "John", 
       "last" : "Backus" 
     }, 
     "awards" : { 
       "award" : "Draper Prize", 
       "year" : 1967, 
       "by" : "National Academy of Engineering" 
     } 
} 
{ 
     "_id" : 2, 
     "name" : { 
       "first" : "John", 
       "last" : "McCarthy" 
     }, 
     "awards" : { 
       "award" : "Kyoto Prize", 
       "year" : 1967, 
       "by" : "Inamori Foundation" 
     } 
} 

正如你所看到的，將會複製該文件（所以約翰·巴庫斯的文檔返回兩次）的其餘部分，但你可以通過添加一個$group來改變，例如

db.bios.aggregate([ { $match : {"awards.year":1967} },  
    { $unwind : "$awards"},  
    { $match : {"awards.year" :1967} }, 
    { $group : { _id : "$_id", "awards" : { $push : "$awards" } } } 
]).pretty(); 

但是有很多方法可以做到這一點，所以我建議您深入研究文檔以獲取所需的投影。