Add connected_at field to $events/client_disconected

Author: Meggielqk

en_US/data-integration/rule-sql-events-and-fields.md

@@ -332,14 +332,15 @@ Refer to the table below for fields that can be selected from the received MQTT
 
 This event topic can be used to trigger a rule when a client is disconnected.
 
-For example, you can use the statement below to extract data from the `"$events/client_disconnected"` event topic that includes the following data fields: client ID, username, disconnect reason, disconnect time, and EMQX node where the event is triggered.
+For example, you can use the statement below to extract data from the `"$events/client_disconnected"` event topic that includes the following data fields: client ID, username, disconnect reason, connection start time, disconnect time, and EMQX node where the event is triggered.
 
 Example:
 ```sql
 SELECT
   clientid,
   username,
   reason,
+  connected_at,
   disconnected_at,
   node
 FROM
@@ -351,20 +352,20 @@ Output:
   "username": "u_emqx",
   "reason": "normal",
   "node": "[email protected]",
+  "connected_at": 1645003578036,
   "disconnected_at": 1645003578536,
   "clientid": "c_emqx"
 }
 ```
 
-
-
 | Field             | Explanation                                                  |
 | :---------------- | :----------------------------------------------------------- |
 | `reason`          | Disconnect reasons<br/><br/>`normal`: The client is intentionally disconnected <br/><br/>`kicked`: EMQX has forcibly removed the client through REST API<br/><br/>`keepalive_timeout`: The specified keepalive time period expired.<br/><br/>`not_authorized`: Authorization failed.<br/><br/>`tcp_closed`: The peer has closed network connection.<br/><br/>`discarded`: Another client ( with `clean_start` set to `true`) connected with the same ClientID, causing the previous connection to be dropped.<br/><br/>`takenover`: Another client ( with `clean_start` set to `false`) connected with the same ClientID, taking over the previous connection..<br/><br/>`internal_error`: An error has occurred due to an improperly formatted message or other unknown issues. |
 | `clientid`        | Client ID                                                    |
 | `username`        | Client username                                              |
 | `peername`        | IP Address and Port number                                   |
 | `sockname`        | IP Address and Port number listened by EMQX                  |
+| `connected_at` | Client connection start time (unit: ms). This timestamp represents when the current session was established and helps identify which connection session the disconnect event belongs to.<br />It ensures that delayed disconnect events do not overwrite newer connection states. |
 | `disconnected_at` | Client disconnection completion time (unit: ms)              |
 | `disconn_props`   | DISCONNECT Properties (MQTT 5.0 clients only)                |
 | `timestamp`       | Event trigger time (unit: ms)                                |

zh_CN/data-integration/rule-sql-events-and-fields.md

@@ -347,6 +347,7 @@ FROM
 | username         | 消息目的用户名                                               |
 | peername         | 客户端的 IPAddress 和 Port                                   |
 | sockname         | emqx 监听的 IPAddress 和 Port                                |
+| connected_at | 客户端连接开始时间（单位：毫秒）。该时间戳表示当前会话建立的时间，有助于识别断开事件所属的连接会话。<br />此字段可确保延迟的断开事件不会覆盖较新的连接状态。 |
 | disconnected\_at | 客户端连接断开时间 (单位：毫秒)                              |
 | disconn\_props   | DISCONNECT Properties (仅适用于 MQTT 5.0)                    |
 | timestamp        | 事件触发时间 (单位：毫秒)                                    |
@@ -360,6 +361,7 @@ SELECT
   clientid,
   username,
   reason,
+  connected_at,
   disconnected_at,
   node
 FROM
@@ -373,6 +375,7 @@ FROM
   "username": "u_emqx",
   "reason": "normal",
   "node": "[email protected]",
+  "connected_at": 1645003578036,
   "disconnected_at": 1645003578536,
   "clientid": "c_emqx"
 }