聚合查询
对查询的结果进行统计，分组等操作的时候就需要用的聚合操作， 聚合操作需要用到聚合操作对应的参数。参数字段名叫：aggs。
分组统计(terms)
{
"aggs": {
// 聚合操作
"category_group":{
// 名称，随意取名
"terms":{
"field":"price"
}
}
}
}
返回内容
{
"took": 2,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 3,
"relation": "eq"
},
"max_score": 1.0,
"hits": [
{
"_index": "shopping",
"_type": "_doc",
"_id": "1001",
"_score": 1.0,
"_source": {
"title": "水星家纺被子夏季空调被 夏凉被夏天被子双人夏被被芯学生宿舍被子200*230cm",
"category": "床上用品",
"image": "https://img11.360buyimg.com/n7/jfs/t1/191056/14/24248/144443/62767f75E23ccafc4/5110691845cfa4cf.jpg",
"price": 169.0
}
},
{
"_index": "shopping",
"_type": "_doc",
"_id": "1002",
"_score": 1.0,
"_source": {
"title": "水星家纺 60S长绒棉贡缎床上四件套 酒店高档纯棉床单被套枕套 被罩被单1.8米床乔伊斯玫瑰(海蓝色/抗菌)",
"category": "床上用品",
"image": "https://www.shuixing.com/pc/images/2022/logo_02.png",
"price": 899.0
}
},
{
"_index": "shopping",
"_type": "_doc",
"_id": "1003",
"_score": 1.0,
"_source": {
"title": "华为手机",
"category": "3C数码",
"image": "https://img10.360buyimg.com/n7/jfs/t1/111175/35/24913/81730/625ed1a5Ed8f452a3/d0370cd4e6837908.jpg",
"price": 1699.0
}
}
]
},
"aggregations": {
"category_group": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": 169.0,
"doc_count": 1
},
{
"key": 899.0,
"doc_count": 1
},
{
"key": 1699.0,
"doc_count": 1
}
]
}
}
}
从返回结果中还包含了元素的数据信息。如果要取消原数据的获取，那再添加一个size参数即可。
{
"aggs": {
// 聚合操作
"category_group":{
// 名称，随意取名
"terms":{
"field":"price"
}
}
},
"size":0 // 表示取得原数据0条，这个也是分页查询的内容。
}
这时返回的数据就是：
{
"took": 6,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 3,
"relation": "eq"
},
"max_score": null,
"hits": []
},
"aggregations": {
"category_group": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": 169.0,
"doc_count": 1
},
{
"key": 899.0,
"doc_count": 1
},
{
"key": 1699.0,
"doc_count": 1
}
]
}
}
}
取平均值（avg）
获取价格的平均值，请求体
{
"aggs": {
// 聚合操作
"category_group":{
// 名称，随意取名
"avg":{
"field":"price"
}
}
},
"size":0 // 表示取得原数据0条，这个也是分页查询的内容。
}
响应内容
{
"took": 3,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 3,
"relation": "eq"
},
"max_score": null,
"hits": []
},
"aggregations": {
"category_group": {
"value": 922.3333333333334
}
}
}