加入了 聊天记录总行数内容，并且处理了聊天参与者出现退群时无昵称的bug

message_storage/message_to_db.py

@@ -70,12 +70,14 @@ def get_messages(group_id, all_contacts: dict):
 
             # 提取结果并组成带逗号的字符串
             result = []
+            if cursor.rowcount > 0:
+                result.append(f"聊天记录总行数：{cursor.rowcount}")
             for row in cursor.fetchall():
                 group_id = row[0]
                 timestamp = row[1]
                 sender = row[2]
                 content = row[3]
-                result.append(f"{group_id},{timestamp},{all_contacts[sender]},{content}")
+                result.append(f"{group_id},{timestamp},{all_contacts.get(sender, sender)},{content}")
 
             # 将列表中的字符串连接成一个最终的结果
             result_str = "\n".join(result)