原文地址: https://www.elastic.co/guide/en/elasticsearch/reference/7.7/search-aggregations-bucket-nested-aggregation.html, 原文档版权归 www.elastic.co 所有
IMPORTANT: No additional bug fixes or documentation updates
will be released for this version. For the latest information, see the
current release documentation.
Nested Aggregationedit
A special single bucket aggregation that enables aggregating nested documents.
For example, lets say we have an index of products, and each product holds the list of resellers - each having its own price for the product. The mapping could look like:
PUT /products
{
"mappings": {
"properties" : {
"resellers" : {
"type" : "nested",
"properties" : {
"reseller" : { "type" : "text" },
"price" : { "type" : "double" }
}
}
}
}
}
The following request adds a product with two resellers:
PUT /products/_doc/0
{
"name": "LED TV",
"resellers": [
{
"reseller": "companyA",
"price": 350
},
{
"reseller": "companyB",
"price": 500
}
]
}
The following request returns the minimum price a product can be purchased for:
GET /products/_search
{
"query" : {
"match" : { "name" : "led tv" }
},
"aggs" : {
"resellers" : {
"nested" : {
"path" : "resellers"
},
"aggs" : {
"min_price" : { "min" : { "field" : "resellers.price" } }
}
}
}
}
As you can see above, the nested aggregation requires the path of the nested documents within the top level documents.
Then one can define any type of aggregation over these nested documents.
Response:
{
...
"aggregations": {
"resellers": {
"doc_count": 2,
"min_price": {
"value": 350
}
}
}
}