cardinality 即去重计算,类似sql中 count(distinct),先去重再求和,计算指定field值的种类数。
下面实例,计算有多少个不同的city。
请求:
POST bank/_doc/_search
{
"size": 0,
"aggs": {
"cartinality_gender": {
"cardinality": {
"field": "city.keyword"
}
}
}
}
响应:
{
"took": 2,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"skipped": 0,
"failed": 0
},
"hits": {
"total": 15,
"max_score": 0,
"hits": []
},
"aggregations": {
"cartinality_gender": {
"value": 15
}
}
}