在 ElasticSearch 中,如何计算满足特定条件的嵌套字段(即嵌套对象列表)的对象?
例子
有 Customer 索引,类型 Customer 有一个 Services 嵌套字段,结构如下:
public class Customer
{
public int Id;
public List<Service> Services;
}
public class Service
{
public int Id;
public DateTime Date;
public decimal Rating;
}
我如何计算 2017 年 6 月发生且评分高于 5 的所有服务?
好问题 :) 为了得到你想要的东西,你应该预先定义你的映射,并且嵌套的属性映射工作得很好。
该嵌套类型是该对象的数据类型,它允许对象的数组要索引和查询的专用版本独立的彼此。https://www.elastic.co/guide/en/elasticsearch/reference/2.4/nested.html
请在下面找到完整的例子:)
映射
PUT example_nested_test
{
"mappings": {
"nested": {
"properties": {
"Id": {
"type": "long"
},
"Services": {
"type": "nested",
"properties": {
"Id": {
"type": "long"
},
"Date": {
"type": "date"
},
"Rating": {
"type": "long"
}
}
}
}
}
}
}
发布数据
POST example_nested_test/nested/100
{
"Id" : 1,
"Services": [
{
"Id": 1,
"Date" :"2017-05-10",
"Rating" : 5
},
{
"Id": 2,
"Date" :"2013-05-10",
"Rating" : 2
},
{
"Id": 4,
"Date" :"2017-05-10",
"Rating" : 6
}]
}
询问
GET example_nested_test/_search
{
"size":0,
"aggs": {
"Services": {
"nested": {
"path": "Services"
},
"aggs": {
"Rating": {
"filter": {
"bool": {
"must": [
{
"range": {
"Services.Date": {
"gt": "2017",
"format": "yyyy"
}
}
},
{
"range": {
"Services.Rating": {
"gt": "5"
}
}
}
]
}
}
}
}
}
}
}
结果:
"aggregations": {
"Services": {
"doc_count": 3,
"Rating": {
"doc_count": 1
}
}
}
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