java中的Mongo聚合

Hi my mongo collections包含以下文档：

  {
      "_id" : ObjectId("539efd5b254bb5f65c9da94e"),
      "iInfo" : [ 
          { "ifout" : 0, "iferror" : 0, "ifdes" : "N/A", "ifin" : 0 },
          { "ifout" : 0, "iferror" : 10, "ifdes" : "N/A", "ifin" : 0 },
          { "ifout" : 0, "iferror" : 4, "ifdes" : "N/A", "ifRemotePort" : "0", "ifin" : 0 },
          { "ifout" : 0, "iferror" : 0, "ifdes" : "N/A", "ifin" : 0 } 
      ]
  }
  { 
      "_id" : ObjectId("539efd76254bb5f65c9da94f"),
      "iInfo" : [ 
          { "ifout" : 0, "iferror" : 0, "ifdes" : "N/A", "ifin" : 0 },
          { "ifout" : 0, "iferror" : 7, "ifdes" : "N/A", "ifin" : 0 },
          { "ifout" : 0, "iferror" : 4, "ifdes" : "N/A", "ifRemotePort" : "0", "ifin" : 0 },
          { "ifout" : 110, "iferror" : 0, "ifdes" : "N/A", "ifin" : 0 }
          { "ifout" : 90, "iferror" : 0, "ifdes" : "N/A", "ifin" : 0 }
      ]
  }
  {
      "_id" : ObjectId("539efed7254bb5f65c9da950"),
     "iInfo" : [ 
         { "ifout" : 10, "iferror" : 0, "ifdes" : "N/A", "ifin" : 0 }, 
         { "ifout" : 0, "iferror" : 10, "ifdes" : "N/A", "ifin" : 0 },
         { "ifout" : 0, "iferror" : 4, "ifdes" : "N/A", "ifRemotePort" : "0", "ifin" : 0 },
         { "ifout" : 0, "iferror" : 0, "ifdes" : "N/A", "ifin" : 0 }
     ] 
  }
  { 
      "_id" : ObjectId("539efeed254bb5f65c9da951"),
      "iInfo" : [
          { "ifout" : 0, "iferror" : 0, "ifdes" : "N/A", "ifin" : 0 },
          { "ifout" : 0, "iferror" : 10, "ifdes" : "N/A", "ifin" : 0 },
          { "ifout" : 0, "iferror" : 4, "ifdes" : "N/A", "ifRemotePort" : "0", "ifin" : 0 },
          { "ifout" : 100, "iferror" : 0, "ifdes" : "N/A", "ifin" : 0 },
          { "ifout" : 210, "iferror" : 0, "ifdes" : "N/A", "ifin" : 0 }
      ]
  }

现在我想对这些文档进行如下排序：

  { 
      "_id" : ObjectId("539efeed254bb5f65c9da951"),
      "iInfo" : [ 
          { "out" : 210,"iferror" : 0,"ifdes" : "N/A","ifin" : 0} 
      ]
  }
{ 
      "_id" : ObjectId("539efd76254bb5f65c9da94f"),
      "iInfo" : [ 
          { "out" : 110,"iferror" : 0,"ifdes" : "N/A","ifin" : 0} 
      ]
  }
{ 
      "_id" : ObjectId("539efeed254bb5f65c9da951"),
      "iInfo" : [ 
          { "out" : 100,"iferror" : 0,"ifdes" : "N/A","ifin" : 0} 
      ]
  }
  { 
      "_id" : ObjectId("539efed7254bb5f65c9da950"),
      "iInfo" : [
          { "out" : 90,"iferror" : 0,"ifdes" : "N/A","ifin" : 0} 
      ]
  }

{
    "_id" : ObjectId("539efeed254bb5f65c9da951"),
    "iInfo" : [ 
        { "out" : 100 }, 
        { "out" : 0 },
        { "out" : 0 }, 
        { "out" : 0 }
    ]
}
{ 
    "_id" : ObjectId("539efed7254bb5f65c9da950"),
    "iInfo" : [ 
        { "out" : 10 },
        { "out" : 0 },
        { "out" : 0 },
        { "out" : 0 }
    ]
}
{
    "_id" : ObjectId("539efd76254bb5f65c9da94f"),
    "iInfo" : [
        { "out" : 90 },
        { "out" : 0 },
        { "out" : 0 },
        { "out" : 0 } 
    ]
}
{
    "_id" : ObjectId("539efd5b254bb5f65c9da94e"),
    "iInfo" : [
        { "out" : 0 },
        { "out" : 0 },
        { "out" : 0 },
        { "out" : 0 }
    ]
}

为此，我编写了我的mongo查询，如下所示

db.demo.aggregate([
    { "$project": { "_id": 1, "out": "$iInfo.ifout"} },
    { "$unwind": "$out" },
    { "$sort": { "_id": 1, "out": -1 } },
    { "$group": { "_id": "$_id" , "iInfo": { "$push": { "out":"$out" } } } }
 ])

上述查询返回如下输出：

  { 
      "_id" : ObjectId("539efeed254bb5f65c9da951"),
      "iInfo" : [ 
          { "out" : 210,"iferror" : 0,"ifdes" : "N/A","ifin" : 0} 
      ]
  }
{ 
      "_id" : ObjectId("539efd76254bb5f65c9da94f"),
      "iInfo" : [ 
          { "out" : 110,"iferror" : 0,"ifdes" : "N/A","ifin" : 0} 
      ]
  }
{ 
      "_id" : ObjectId("539efeed254bb5f65c9da951"),
      "iInfo" : [ 
          { "out" : 100,"iferror" : 0,"ifdes" : "N/A","ifin" : 0} 
      ]
  }
  { 
      "_id" : ObjectId("539efed7254bb5f65c9da950"),
      "iInfo" : [
          { "out" : 90,"iferror" : 0,"ifdes" : "N/A","ifin" : 0} 
      ]
  }

{
    "_id" : ObjectId("539efeed254bb5f65c9da951"),
    "iInfo" : [ 
        { "out" : 100 }, 
        { "out" : 0 },
        { "out" : 0 }, 
        { "out" : 0 }
    ]
}
{ 
    "_id" : ObjectId("539efed7254bb5f65c9da950"),
    "iInfo" : [ 
        { "out" : 10 },
        { "out" : 0 },
        { "out" : 0 },
        { "out" : 0 }
    ]
}
{
    "_id" : ObjectId("539efd76254bb5f65c9da94f"),
    "iInfo" : [
        { "out" : 90 },
        { "out" : 0 },
        { "out" : 0 },
        { "out" : 0 } 
    ]
}
{
    "_id" : ObjectId("539efd5b254bb5f65c9da94e"),
    "iInfo" : [
        { "out" : 0 },
        { "out" : 0 },
        { "out" : 0 },
        { "out" : 0 }
    ]
}

---

那么，如何使用mongo和java代码获得所需的输出呢？

大致正确，但由于您似乎想要最高的排序值，因此您需要在以下情况下使用运算符进行过滤：

db.demo.aggregate([
//将文档与数组中的非0值匹配
{“$match”：{“iInfo.ifout”：{“$ne”：0}}，
//展开阵列
{“$unwind”：“$iInfo”}，
//筛选所有具有0的数组元素-同时删除所有为0的文档
{“$match”：{“iInfo.ifout”：{“$ne”：0}}，
//对文档中的数组元素进行排序
{“$sort”：{“_id”：-1，“iInfo.ifout”：-1}，
//每个文档只取“第一个”数组元素
{“$组”：{
“\u id”：“$\u id”，
“Iifout”：{“$first”：“$iInfo.ifout”}，
“Iiferror”：{“$first”：“$iInfo.iferror”}，
“Iifdes”：{“$first”：“$iInfo.ifdes”}，
“Iifin”：{“$first”：“$iInfo.ifin”}
}},
//组将这些结果作为数组推送
{“$组”：{
“\u id”：“$\u id”，
“信息”：{
“$push”：{
“ifout”：“$ifout”，
“Iferor”：“$Iiferror”，
“Iifdes”：“$Iifdes”，
“Iifin”：“$Iifin”
}
}
}}
])

还要注意，您所需的输出是按降序排列的

---

与的聚合操作是独立的，并且您不能在“组”阶段使用子文档键，因此，如果您希望将内容作为数组返回，则需要按照第二个管道执行，如图所示，以便将值作为数组字段。

您是否使用Java驱动程序？您的查询代码是JavaScript，它将从终端运行……Hi@Kyte我也使用了java驱动器，但我希望两种查询都使用mongo和java。我在java中尝试过，但没有找到任何解决方案。这个问题可能有帮助，或者这个问题可能有助于hi-it正常工作，而不是“$sort”：{“\u id”：-11我将“$sort”：{“\u id”：-1替换为它work@yogesh只是打字错误，我一定是“胖手指”输入时会出现这种情况。@yogesh我相信是的。当有人帮你解决问题时，这里通常使用Accept和upvote。嗨，我可以在mongo中更改我的输出结构，有什么提示或帮助吗？@yogesh我看不到输出与你发布的内容有什么不同。唯一可能的区别是所有0值的文档earing.现在管道中还有其他的

$match

过滤器。