求平均数

{  "query": {    "bool": {      "must": [        {          "term": {            "store_id": "9167c916-0bf2-4473-b2a0-ab445deeea48"          }        },        {          "range": {            "buss_date": {              "gte": "2018-5-28",              "lte": "2018-6-24"            }          }        }      ],      "must_not": [],      "should": []    }  },  "from": 0,  "size": 10,  "sort": {    "buss_date": {      "order": "desc"    }  },  "aggs": {    "avg_dinner_open_tabs": {      "avg": {        "field": "dinner_open_tabs"      }    }  },  "_source": [    "dinner_open_tabs",    "buss_date"  ]}