diff --git a/elastic search/elastic search.md b/elastic search/elastic search.md
index 8000628..80c7f65 100644
--- a/elastic search/elastic search.md	
+++ b/elastic search/elastic search.md	
@@ -1273,4 +1273,227 @@ GET kibana_sample_data_ecommerce/_search
 > 基于es的分布式结构，`terms aggregations`在多个shards上运行时，document计数可能会有小的误差，`doc_count_error_upper_bound`的代表计数的最大可能误差
 
 - sum_other_doc_count: 由于当前请求体中设置了`aggs.sales_by_category.terms.size`为5，故而`sum_other_doc_count`代表未包含在返回结果中的文档数量
-- 
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+- aggregations.buckets： 该字段代表category buckets数组，根据count来排序
+
+#### date_histogram
+`date_histogram`类型的聚合会将文档聚合为time-based buckets，其类似于terms，但是其并非基于精确匹配的聚合，而是基于日期的集合。
+
+`date_histogram`聚合示例如下：
+```
+GET kibana_sample_data_ecommerce/_search
+{
+ "size": 0,
+ "aggs": {
+   "daily_orders": { 
+     "date_histogram": { 
+       "field": "order_date",
+       "calendar_interval": "day", 
+       "format": "yyyy-MM-dd", 
+       "min_doc_count": 0 
+     }
+   }
+ }
+}
+```
+上述示例中，各参数含义如下：
+- `min_doc_count`：当min_doc_count被设置为0时，会返回没有订单的天数
+
+请求返回结果如下：
+```
+{
+  "took": 2,
+  "timed_out": false,
+  "_shards": {
+    "total": 5,
+    "successful": 5,
+    "skipped": 0,
+    "failed": 0
+  },
+  "hits": {
+    "total": {
+      "value": 4675,
+      "relation": "eq"
+    },
+    "max_score": null,
+    "hits": []
+  },
+  "aggregations": {
+    "daily_orders": { 
+      "buckets": [ 
+        {
+          "key_as_string": "2024-11-28", 
+          "key": 1732752000000, 
+          "doc_count": 146 
+        },
+        {
+          "key_as_string": "2024-11-29",
+          "key": 1732838400000,
+          "doc_count": 153
+        },
+        {
+          "key_as_string": "2024-11-30",
+          "key": 1732924800000,
+          "doc_count": 143
+        },
+        {
+          "key_as_string": "2024-12-01",
+          "key": 1733011200000,
+          "doc_count": 140
+        },
+        {
+          "key_as_string": "2024-12-02",
+          "key": 1733097600000,
+          "doc_count": 139
+        },
+        {
+          "key_as_string": "2024-12-03",
+          "key": 1733184000000,
+          "doc_count": 157
+        },
+        {
+          "key_as_string": "2024-12-04",
+          "key": 1733270400000,
+          "doc_count": 145
+        },
+        {
+          "key_as_string": "2024-12-05",
+          "key": 1733356800000,
+          "doc_count": 152
+        },
+        {
+          "key_as_string": "2024-12-06",
+          "key": 1733443200000,
+          "doc_count": 163
+        },
+        {
+          "key_as_string": "2024-12-07",
+          "key": 1733529600000,
+          "doc_count": 141
+        },
+        {
+          "key_as_string": "2024-12-08",
+          "key": 1733616000000,
+          "doc_count": 151
+        },
+        {
+          "key_as_string": "2024-12-09",
+          "key": 1733702400000,
+          "doc_count": 143
+        },
+        {
+          "key_as_string": "2024-12-10",
+          "key": 1733788800000,
+          "doc_count": 143
+        },
+        {
+          "key_as_string": "2024-12-11",
+          "key": 1733875200000,
+          "doc_count": 142
+        },
+        {
+          "key_as_string": "2024-12-12",
+          "key": 1733961600000,
+          "doc_count": 161
+        },
+        {
+          "key_as_string": "2024-12-13",
+          "key": 1734048000000,
+          "doc_count": 144
+        },
+        {
+          "key_as_string": "2024-12-14",
+          "key": 1734134400000,
+          "doc_count": 157
+        },
+        {
+          "key_as_string": "2024-12-15",
+          "key": 1734220800000,
+          "doc_count": 158
+        },
+        {
+          "key_as_string": "2024-12-16",
+          "key": 1734307200000,
+          "doc_count": 144
+        },
+        {
+          "key_as_string": "2024-12-17",
+          "key": 1734393600000,
+          "doc_count": 151
+        },
+        {
+          "key_as_string": "2024-12-18",
+          "key": 1734480000000,
+          "doc_count": 145
+        },
+        {
+          "key_as_string": "2024-12-19",
+          "key": 1734566400000,
+          "doc_count": 157
+        },
+        {
+          "key_as_string": "2024-12-20",
+          "key": 1734652800000,
+          "doc_count": 158
+        },
+        {
+          "key_as_string": "2024-12-21",
+          "key": 1734739200000,
+          "doc_count": 153
+        },
+        {
+          "key_as_string": "2024-12-22",
+          "key": 1734825600000,
+          "doc_count": 165
+        },
+        {
+          "key_as_string": "2024-12-23",
+          "key": 1734912000000,
+          "doc_count": 153
+        },
+        {
+          "key_as_string": "2024-12-24",
+          "key": 1734998400000,
+          "doc_count": 158
+        },
+        {
+          "key_as_string": "2024-12-25",
+          "key": 1735084800000,
+          "doc_count": 160
+        },
+        {
+          "key_as_string": "2024-12-26",
+          "key": 1735171200000,
+          "doc_count": 159
+        },
+        {
+          "key_as_string": "2024-12-27",
+          "key": 1735257600000,
+          "doc_count": 152
+        },
+        {
+          "key_as_string": "2024-12-28",
+          "key": 1735344000000,
+          "doc_count": 142
+        }
+      ]
+    }
+  }
+}
+```
+上述示例中，`key_as_string`为`human readable`日期字符串，而`key`则是和`key_as_string`代表相同日期的unix时间戳。
+
+`doc_count`代表bucket中的文档个数。
+
+##### Calendar intervals
+`calendar-aware interval`可以通过`calendar_interval`来进行配置，可以通过时间单位名称`month`或单个时间单位`1M`来进行指定。类似的`day`和`1d`也是等同的，`但是，并不支持2d这种多个时间单位的配置`。
+
+可以接受的时间单位为：
+- `minute, 1m`
+- `hour, 1h`
+- `day, 1d`
+- `week, 1w`
+- `month, 1M`
+- `quarter, 1q`
+- `year, 1y`
+
+#### 
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