elastic search6.2.2 实现用户搜索记录查询（去重、排序）

//我的搜索
PUT my_search
{
    "settings":{
        "number_of_replicas": 0
    },
    "mappings":{
        "_doc":{
            "properties":{
                "user": {"type": "integer"},
                "word": {"type": "keyword"},
                "datetime": {
                    "type": "date",
                    "format": "yyyy-MM-dd HH:mm:ss||yyyy-MM-dd||epoch_millis"
                }
            }
        }
    }
}

POST my_search/_doc
// 自动生成ID

{
    "user": 1,
    "word": "区块链",
    "datetime":"2018-02-08 23:58:59"
}


{
    "user": 1,
    "word": "刘平",
    "datetime":"2018-03-08 23:58:59"
}

{
    "user": 1,
    "word": "你好",
    "datetime":"2018-04-08 23:58:59"
}


{
    "user": 1,
    "word": "我好",
    "datetime":"2018-05-08 23:59:59"
}


{
    "user": 1,
    "word": "你好",
    "datetime":"2018-06-08 23:58:59"
}


{
    "user": 1,
    "word": "他好",
    "datetime":"2018-07-09 23:58:59"
}


{
    "user": 1,
    "word": "他好",
    "datetime":"2018-08-09 23:58:59"
}

POST my_search/_search
// 我的最近搜索记录(展示10条)
{
    "query":{
        "match":{
            "user":"1"
        }
    },
    "aggs":{
        "my_so":{
            "terms":{
                "field":"word",
                "size":10,
                "order":{
                    "max_time":"desc"
                }
            },
            "aggs":{
                "max_time":{
                    "max":{
                        "field":"datetime"
                    }
                }
            }
        }
    },
    "size":0,
    "from":0
}