一、两个核心概念：bucket和metric 1.1 bucket 有如下数据 city name 北京 张三 北京 李四 天津 王五 天津 赵六 天津 王麻子 划分出来两个bucket，一个是北京bucket，一个是天津bucket 北京bucket：包
有如下数据
city name 北京 张三 北京 李四 天津 王五 天津 赵六 天津 王麻子划分出来两个bucket，一个是北京bucket，一个是天津bucket
北京bucket：包含了2个人，张三，李四
上海bucket：包含了3个人，王五，赵六，王麻子
1.2 metricmetric，就是对一个bucket执行的某种聚合分析的操作，比如说求平均值，求最大值，求最小值
比如下面的一个sql语句
select count(*) from book group studymodelbucket：group by studymodel --> 那些studymodel相同的数据，就会被划分到一个bucket中
metric：count(*)，对每个bucket中所有的数据，计算一个数量。例如avg()，sum()，max()，min()
二、聚合示例 2.1 数据准备首先创建book索引
PUT /book/
{
"settings": {
"number_of_shards": 1,
"number_of_replicas": 0
},
"mappings": {
"properties": {
"name": {
"type": "text",
"analyzer": "ik_max_word",
"search_analyzer": "ik_smart"
},
"description": {
"type": "text",
"analyzer": "ik_max_word",
"search_analyzer": "ik_smart"
},
"studymodel": {
"type": "keyword"
},
"price": {
"type": "double"
},
"timestamp": {
"type": "date",
"format": "yyyy-MM-dd HH:mm:ss||yyyy-MM-dd||epoch_millis"
},
"pic": {
"type": "text",
"index": false
}
}
}
}添加测试数据
PUT /book/_doc/1
{
"name": "Bootstrap开发",
"description": "Bootstrap是一个非常流行的开发框架。此开发框架可以帮助不擅长css页面开发的程序人员轻松的实现一个css，不受浏览器限制的精美界面css效果。",
"studymodel": "201002",
"price": 38.6,
"timestamp": "2019-08-25 19:11:35",
"pic": "group1/M00/00/00/wKhlQFs6RCeAY0pHAAJx5ZjNDEM428.jpg",
"tags": [
"bootstrap",
"dev"
]
}
PUT /book/_doc/2
{
"name": "java编程思想",
"description": "java语言是世界第一编程语言，在软件开发领域使用人数最多。",
"studymodel": "201001",
"price": 68.6,
"timestamp": "2019-08-25 19:11:35",
"pic": "group1/M00/00/00/wKhlQFs6RCeAY0pHAAJx5ZjNDEM428.jpg",
"tags": [
"java",
"dev"
]
}
PUT /book/_doc/3
{
"name": "spring开发基础",
"description": "spring 在java领域非常流行，java程序员都在用。",
"studymodel": "201001",
"price": 88.6,
"timestamp": "2019-08-24 19:11:35",
"pic": "group1/M00/00/00/wKhlQFs6RCeAY0pHAAJx5ZjNDEM428.jpg",
"tags": [
"spring",
"java"
]
}sql语句： select studymodel，count(*) from book group by studymodel
"size": 0, ==> 作用 ：只需要聚合的数据，不需要查询的数据
GET /book/_search
{
"size": 0,
"query": {
"match_all": {}
},
"aggs": {
"group_by_model": {
"terms": {
"field": "studymodel"
}
}
}
}结果：
{
"took" : 2,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 3,
"relation" : "eq"
},
"max_score" : null,
"hits" : [ ]
},
"aggregations" : {
"group_by_model" : {
"doc_count_error_upper_bound" : 0,
"sum_other_doc_count" : 0,
"buckets" : [
{
"key" : "201001",
"doc_count" : 2
},
{
"key" : "201002",
"doc_count" : 1
}
]
}
}
}设置字段"fielddata": true，不设置会报错
PUT /book/_mapping/
{
"properties": {
"tags": {
"type": "text",
"fielddata": true
}
}
}查询
GET /book/_search
{
"size": 0,
"query": {
"match_all": {}
},
"aggs": {
"group_by_tags": {
"terms": { "field": "tags" }
}
}
}结果：
{
"took" : 2,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 3,
"relation" : "eq"
},
"max_score" : null,
"hits" : [ ]
},
"aggregations" : {
"group_by_tags" : {
"doc_count_error_upper_bound" : 0,
"sum_other_doc_count" : 0,
"buckets" : [
{
"key" : "dev",
"doc_count" : 2
},
{
"key" : "java",
"doc_count" : 2
},
{
"key" : "bootstrap",
"doc_count" : 1
},
{
"key" : "spring",
"doc_count" : 1
}
]
}
}
}GET /book/_search
{
"size": 0,
"query": {
"match": {
"description": "java程序员"
}
},
"aggs": {
"group_by_tags": {
"terms": { "field": "tags" }
}
}
}结果：
{
"took" : 70,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 2,
"relation" : "eq"
},
"max_score" : null,
"hits" : [ ]
},
"aggregations" : {
"group_by_tags" : {
"doc_count_error_upper_bound" : 0,
"sum_other_doc_count" : 0,
"buckets" : [
{
"key" : "java",
"doc_count" : 2
},
{
"key" : "dev",
"doc_count" : 1
},
{
"key" : "spring",
"doc_count" : 1
}
]
}
}
}子聚合
GET /book/_search
{
"size": 0,
"aggs": {
"group_by_tags": {
"terms": {
"field": "tags"
},
"aggs": {
"avg_price": {
"avg": {
"field": "price"
}
}
}
}
}
}结果：
{
"took" : 0,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 3,
"relation" : "eq"
},
"max_score" : null,
"hits" : [ ]
},
"aggregations" : {
"group_by_tags" : {
"doc_count_error_upper_bound" : 0,
"sum_other_doc_count" : 0,
"buckets" : [
{
"key" : "dev",
"doc_count" : 2,
"avg_price" : {
"value" : 53.599999999999994
}
},
{
"key" : "java",
"doc_count" : 2,
"avg_price" : {
"value" : 78.6
}
},
{
"key" : "bootstrap",
"doc_count" : 1,
"avg_price" : {
"value" : 38.6
}
},
{
"key" : "spring",
"doc_count" : 1,
"avg_price" : {
"value" : 88.6
}
}
]
}
}
}小技巧，如果是查询全部，match_all可省略
GET /book/_search
{
"size": 0,
"aggs": {
"group_by_tags": {
"terms": {
"field": "tags",
"order": {
"avg_price": "desc"
}
},
"aggs": {
"avg_price": {
"avg": {
"field": "price"
}
}
}
}
}
}结果：
{
"took" : 4,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 3,
"relation" : "eq"
},
"max_score" : null,
"hits" : [ ]
},
"aggregations" : {
"group_by_tags" : {
"doc_count_error_upper_bound" : 0,
"sum_other_doc_count" : 0,
"buckets" : [
{
"key" : "spring",
"doc_count" : 1,
"avg_price" : {
"value" : 88.6
}
},
{
"key" : "java",
"doc_count" : 2,
"avg_price" : {
"value" : 78.6
}
},
{
"key" : "dev",
"doc_count" : 2,
"avg_price" : {
"value" : 53.599999999999994
}
},
{
"key" : "bootstrap",
"doc_count" : 1,
"avg_price" : {
"value" : 38.6
}
}
]
}
}
}GET /book/_search
{
"size": 0,
"aggs": {
"group_by_price": {
"range": {
"field": "price",
"ranges": [
{
"from": 0,
"to": 40
},
{
"from": 40,
"to": 60
},
{
"from": 60,
"to": 80
}
]
},
"aggs": {
"group_by_tags": {
"terms": {
"field": "tags"
},
"aggs": {
"average_price": {
"avg": {
"field": "price"
}
}
}
}
}
}
}
}结果：
{
"took" : 5,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 3,
"relation" : "eq"
},
"max_score" : null,
"hits" : [ ]
},
"aggregations" : {
"group_by_price" : {
"buckets" : [
{
"key" : "0.0-40.0",
"from" : 0.0,
"to" : 40.0,
"doc_count" : 1,
"group_by_tags" : {
"doc_count_error_upper_bound" : 0,
"sum_other_doc_count" : 0,
"buckets" : [
{
"key" : "bootstrap",
"doc_count" : 1,
"average_price" : {
"value" : 38.6
}
},
{
"key" : "dev",
"doc_count" : 1,
"average_price" : {
"value" : 38.6
}
}
]
}
},
{
"key" : "40.0-60.0",
"from" : 40.0,
"to" : 60.0,
"doc_count" : 0,
"group_by_tags" : {
"doc_count_error_upper_bound" : 0,
"sum_other_doc_count" : 0,
"buckets" : [ ]
}
},
{
"key" : "60.0-80.0",
"from" : 60.0,
"to" : 80.0,
"doc_count" : 1,
"group_by_tags" : {
"doc_count_error_upper_bound" : 0,
"sum_other_doc_count" : 0,
"buckets" : [
{
"key" : "dev",
"doc_count" : 1,
"average_price" : {
"value" : 68.6
}
},
{
"key" : "java",
"doc_count" : 1,
"average_price" : {
"value" : 68.6
}
}
]
}
}
]
}
}
}