48.cartinality的基本用法

主要知识点

• cartinality的用法

 
 

es去重用的是cartinality metric算法，对每个bucket中的指定的field进行去重，然后获取去重后的count，类似于count(distcint)

 
 

cartinality的用法

 
 

GET /tvs/sales/_search

{

"size": 0,

"aggs": {"mouth": {

"date_histogram": {"field": "sold_date","interval": "month"},

"aggs": {"distict_color": {"cardinality": {"field": "brand"}}}

}

}

}

 
 

执行结果如下：

"aggregations": {

"mouth": {

"buckets": [

{

"key_as_string": "2016-05-01T00:00:00.000Z",

"key": 1462060800000,

"doc_count": 1,

"distict_color": {

"value": 1

}

},

{

"key_as_string": "2016-06-01T00:00:00.000Z",

"key": 1464739200000,

"doc_count": 0,

"distict_color": {

"value": 0

}

},