ElasticSeach查询以检索书籍的所有标记

Books 和 Tags 文件。一本书可以有多个标签。

[ElasticsearchType(Name = "Book")]
public class Book
{
    [Keyword(Store = false)]
    public string Id{ get; set; }

    [Keyword(Store = false)]
    public string CoverColor{ get; set; } 

    public List<Tag> tags { get; set; }
}

这是标签的ElasticSearch文档:

[ElasticsearchType(Name = "Tag")]
public class Tag
{
    [Keyword(Store = false)]
    public int Id{ get; set; }

    [Keyword(Store = false)]
    public string Name{ get; set; }
}

{
  "_index": "myindex",
  "_type": "Book",
  "_id": "4d43345fffereredwerw324",
  "_score": 1,
  "_source": {
    "id": "123456",
    "coverColor": "Red",
    "tags": [
      {
        "id": 15,
        "name": "fantasy"
      },
      {
        "id": 2,
        "name": "Science fiction"
      }
    ]
  }
}

我想要的是一个查询,它检索所有的书籍颜色而不重复(假设我有两个红色和四个绿色,我应该得到一个红色和一个绿色),对于每种颜色,我应该获得相关标签的列表(例如,基本上相同颜色下的所有标签)

理想的JSON输出:

result = [
{
   coverColor: "Red",
   tags: [{ id:1, name:"Fantasy"}, {id: 4, name:"Science fiction"}, {id:33, name:"Novel"}]
},
{
   coverColor: "Green",
   tags: [{id: 4, name:"Science fiction"}]
},
{
   coverColor: "White",
   tags: []
}