mongodb聚合嵌入文档值

我正在使用mongodb中的一些聚合函数

假设我有一些这样的文件

 [
 {
    _id: "1",
    periods: [
      {
         _id: "12",
         tables: [
           {
              _id: "121",
              rows: [
                  { _id: "1211", text: "some text"},
                  { _id: "1212", text: "some other text"},
                  { _id: "1213", text: "yet another text"},

              ]
           }
         ]
      },
      {
         _id: "13",
         tables: [
           {
              _id: "131",
              rows: [
                  { _id: "1311", text: "different text"},
                  { _id: "1312", text: "Oh yeah"}                      
              ]
           }
         ]
      }
    ]
 },
 {
    _id: "2",
    periods: [
      {
         _id: "21",
         tables: [
           {
              _id: "212",
              rows: [
                  { _id: "2121", text: "period2 text"},
                  { _id: "2122", text: "period2 other text"},
                  { _id: "2123", text: "period2 yet another text"},

              ]
           }
         ]
      }
    ]
 }
 ]

[ 
    { "$project" : { "text" : "$periods.tables.rows.text" , "_id" : "$_id"}},
    { "$unwind" : "$text"},
    { "$group" : { "_id" : "$_id" , "texts" : { "$addToSet" : "$text"}}},
    { "$project" : { "_id" : 0 , "texts" : 1}} 
]

{ "texts" : [ 
        [ [ "Some text" , "Some other text" , "yet another text"] , [ "different text" , "oh yeah" ] ],
        [ [ "period2 some text", "period2 some other text", "period2 yet another text"]]
    ]}

现在我想使用mongodb查询来检索一个特定顶级项的所有唯一文本

例如，放弃顶部id 1的所有文本。这意味着我想得到这两个句点子树中的所有文本

预期产出如下：

聚合文本筛选_id:1

[
   "some text",
   "some other text",
   "yet another text",
   "different text",
   "Oh yeah"
]

聚合文本筛选_id:2

[
  "period2 some text",
  "period2 some other text",
  "period2 yet another text"
]

到目前为止，我已经成功地聚合了所有文本，但最终以多个数组结束，我还没有成功地使用$match在id上过滤它们

我当前的聚合查询如下所示

 [
 {
    _id: "1",
    periods: [
      {
         _id: "12",
         tables: [
           {
              _id: "121",
              rows: [
                  { _id: "1211", text: "some text"},
                  { _id: "1212", text: "some other text"},
                  { _id: "1213", text: "yet another text"},

              ]
           }
         ]
      },
      {
         _id: "13",
         tables: [
           {
              _id: "131",
              rows: [
                  { _id: "1311", text: "different text"},
                  { _id: "1312", text: "Oh yeah"}                      
              ]
           }
         ]
      }
    ]
 },
 {
    _id: "2",
    periods: [
      {
         _id: "21",
         tables: [
           {
              _id: "212",
              rows: [
                  { _id: "2121", text: "period2 text"},
                  { _id: "2122", text: "period2 other text"},
                  { _id: "2123", text: "period2 yet another text"},

              ]
           }
         ]
      }
    ]
 }
 ]

[ 
    { "$project" : { "text" : "$periods.tables.rows.text" , "_id" : "$_id"}},
    { "$unwind" : "$text"},
    { "$group" : { "_id" : "$_id" , "texts" : { "$addToSet" : "$text"}}},
    { "$project" : { "_id" : 0 , "texts" : 1}} 
]

{ "texts" : [ 
        [ [ "Some text" , "Some other text" , "yet another text"] , [ "different text" , "oh yeah" ] ],
        [ [ "period2 some text", "period2 some other text", "period2 yet another text"]]
    ]}

它给了我这样的结果

 [
 {
    _id: "1",
    periods: [
      {
         _id: "12",
         tables: [
           {
              _id: "121",
              rows: [
                  { _id: "1211", text: "some text"},
                  { _id: "1212", text: "some other text"},
                  { _id: "1213", text: "yet another text"},

              ]
           }
         ]
      },
      {
         _id: "13",
         tables: [
           {
              _id: "131",
              rows: [
                  { _id: "1311", text: "different text"},
                  { _id: "1312", text: "Oh yeah"}                      
              ]
           }
         ]
      }
    ]
 },
 {
    _id: "2",
    periods: [
      {
         _id: "21",
         tables: [
           {
              _id: "212",
              rows: [
                  { _id: "2121", text: "period2 text"},
                  { _id: "2122", text: "period2 other text"},
                  { _id: "2123", text: "period2 yet another text"},

              ]
           }
         ]
      }
    ]
 }
 ]

[ 
    { "$project" : { "text" : "$periods.tables.rows.text" , "_id" : "$_id"}},
    { "$unwind" : "$text"},
    { "$group" : { "_id" : "$_id" , "texts" : { "$addToSet" : "$text"}}},
    { "$project" : { "_id" : 0 , "texts" : 1}} 
]

{ "texts" : [ 
        [ [ "Some text" , "Some other text" , "yet another text"] , [ "different text" , "oh yeah" ] ],
        [ [ "period2 some text", "period2 some other text", "period2 yet another text"]]
    ]}

如果我添加$match:{u id:1}，则不会返回任何结果

有人能帮我解决这个问题吗，或者给我指出一个解决问题的方向。我一直在搜索资源，但似乎没有找到任何关于如何使用这些聚合函数的好文档。mongodb文档只使用简单文档

---

PS我知道我可以使用mapreduce来实现这一点，但我希望能够使用聚合函数来实现这一点。

展开只会降低一个级别，因此如果您愿意，您必须调用所调用级别的倍

[ 
    { "$project" : { "text" : "$periods.tables.rows.text" , "_id" : "$_id"}},
    { "$unwind" : "$text"},
    { "$unwind" : "$text"},
    { "$unwind" : "$text"},
    { "$group" : { "_id" : "$_id" , "texts" : { "$addToSet" : "$text"}}},
    { "$project" : { "_id" : 0 , "texts" : 1}} 
]

它会像你期望的那样工作