范围聚合 range
Range Aggregation
基于多桶聚合，使用户能够定义一组范围，每个范围代表一个桶。
GET /_search
{
"aggs" : {
"price_ranges" : {
"range" : {
"field" : "price",
"ranges" : [
{ "to" : 100.0 },
{ "from" : 100.0, "to" : 200.0 },
{ "from" : 200.0 }
]
}
}
}
}
返回
{
...
"aggregations": {
"price_ranges" : {
"buckets": [
{
"key": "*-100.0",
"to": 100.0,
"doc_count": 2
},
{
"key": "100.0-200.0",
"from": 100.0,
"to": 200.0,
"doc_count": 2
},
{
"key": "200.0-*",
"from": 200.0,
"doc_count": 3
}
]
}
}
}
Keyed Response
将keyed标志设置为true会将一个唯一的字符串键与每个bucket相关联，并将范围作为哈希而不是数组返回：
GET /_search
{
"aggs" : {
"price_ranges" : {
"range" : {
"field" : "price",
"keyed" : true,
"ranges" : [
{ "to" : 100 },
{ "from" : 100, "to" : 200 },
{ "from" : 200 }
]
}
}
}
}
返回
{
...
"aggregations": {
"price_ranges" : {
"buckets": {
"*-100.0": {
"to": 100.0,
"doc_count": 2
},
"100.0-200.0": {
"from": 100.0,
"to": 200.0,
"doc_count": 2
},
"200.0-*": {
"from": 200.0,
"doc_count": 3
}
}
}
}
}
还可以自定义每个范围的key：
GET /_search
{
"aggs" : {
"price_ranges" : {
"range" : {
"field" : "price",
"keyed" : true,
"ranges" : [
{ "key" : "cheap", "to" : 100 },
{ "key" : "average", "from" : 100, "to" : 200 },
{ "key" : "expensive", "from" : 200 }
]
}
}
}
}
返回
{
...
"aggregations": {
"price_ranges" : {
"buckets": {
"cheap": {
"to": 100.0,
"doc_count": 2
},
"average": {
"from": 100.0,
"to": 200.0,
"doc_count": 2
},
"expensive": {
"from": 200.0,
"doc_count": 3
}
}
}
}
}
Script
范围聚合接受脚本参数。此参数允许定义将在聚合执行期间执行的inline script。
GET /_search
{
"aggs" : {
"price_ranges" : {
"range" : {
"script" : {
"lang": "painless",
"source": "doc['price'].value"
},
"ranges" : [
{ "to" : 100 },
{ "from" : 100, "to" : 200 },
{ "from" : 200 }
]
}
}
}
}
也可以使用存储的脚本。下面是一个简单的存储脚本：
POST /_scripts/convert_currency
{
"script": {
"lang": "painless",
"source": "doc[params.field].value * params.conversion_rate"
}
}
这个新的存储脚本可以在范围聚合中使用，如下所示：
GET /_search
{
"aggs" : {
"price_ranges" : {
"range" : {
"script" : {
"id": "convert_currency",
"params": {
"field": "price",
"conversion_rate": 0.835526591
}
},
"ranges" : [
{ "from" : 0, "to" : 100 },
{ "from" : 100 }
]
}
}
}
}
Value Script
让我们假设产品价格是美元，但我们希望得到的价格范围是欧元。我们可以使用价值脚本转换聚合之前的价格（假设转换率为0.8）
GET /sales/_search
{
"aggs" : {
"price_ranges" : {
"range" : {
"field" : "price",
"script" : {
"source": "_value * params.conversion_rate",
"params" : {
"conversion_rate" : 0.8
}
},
"ranges" : [
{ "to" : 35 },
{ "from" : 35, "to" : 70 },
{ "from" : 70 }
]
}
}
}
}
Sub Aggregations
下面的示例不仅将文档“桶”到不同的桶，还计算每个价格范围内的价格统计
GET /_search
{
"aggs" : {
"price_ranges" : {
"range" : {
"field" : "price",
"ranges" : [
{ "to" : 100 },
{ "from" : 100, "to" : 200 },
{ "from" : 200 }
]
},
"aggs" : {
"price_stats" : {
"stats" : { "field" : "price" }
}
}
}
}
}
返回
{
...
"aggregations": {
"price_ranges": {
"buckets": [
{
"key": "*-100.0",
"to": 100.0,
"doc_count": 2,
"price_stats": {
"count": 2,
"min": 10.0,
"max": 50.0,
"avg": 30.0,
"sum": 60.0
}
},
{
"key": "100.0-200.0",
"from": 100.0,
"to": 200.0,
"doc_count": 2,
"price_stats": {
"count": 2,
"min": 150.0,
"max": 175.0,
"avg": 162.5,
"sum": 325.0
}
},
{
"key": "200.0-*",
"from": 200.0,
"doc_count": 3,
"price_stats": {
"count": 3,
"min": 200.0,
"max": 200.0,
"avg": 200.0,
"sum": 600.0
}
}
]
}
}
}
如果子聚合也基于与范围聚合相同的Value source（如上面示例中的统计数据聚合），则可以省略其Value source定义。以下将返回与上述相同的响应：
GET /_search
{
"aggs" : {
"price_ranges" : {
"range" : {
"field" : "price",
"ranges" : [
{ "to" : 100 },
{ "from" : 100, "to" : 200 },
{ "from" : 200 }
]
},
"aggs" : {
"price_stats" : {
"stats" : {}
}
}
}
}
}
我们不需要指定price，因为我们默认从父范围聚合“继承”它