histogram：类似于terms，也是进行bucket分组操作，接收一个field，按照这个field的值的各个范围区间，进行bucket分组操作

"histogram":{ "field": "price","interval": 2000
}

interval：2000，划分范围，0_2000，20004000，4000_6000，60008000，8000~10000，

buckets去根据price的值，比如2500落在哪个区间内，落到2000_{4000，此时就会将这条数据放入2000}4000对应的那个bucket中

bucket划分的方法，terms，将field值相同的数据划分到一个bucket中

histogram，将field处于相同区间的数据划分到一个bucket中

bucket有了之后，一样的，去对每个bucket执行avg，count，sum，max，min，等各种metric操作，聚合分析

GET /tvs/sales/_search
{"size" : 0,"aggs":{"price":{"histogram":{ "field": "price","interval": 2000},"aggs":{"revenue": {"sum": { "field" : "price"}}}}}
}

响应结果

{"took": 14,"timed_out": false,"_shards": {"total": 5,"successful": 5,"skipped": 0,"failed": 0},"hits": {"total": 8,"max_score": 0,"hits": []},"aggregations": {"price": {"buckets": [{"key": 0,"doc_count": 3,"revenue": {"value": 3700}},{"key": 2000,"doc_count": 4,"revenue": {"value": 9500}},{"key": 4000,"doc_count": 0,"revenue": {"value": 0}},{"key": 6000,"doc_count": 0,"revenue": {"value": 0}},{"key": 8000,"doc_count": 1,"revenue": {"value": 8000}}]}}
}