我有一个记录消息的表，对于每个操作，都有几条带有时间戳的消息。我需要获取每个操作 ID 的最后一条消息。
示例数据：
timestamp | operation_id | message
---------------------------|--------------------------------------------------------
10/2/2019, 10:00:10.000 AM | 1 | message (last msg for this operation id)
10/2/2019, 10:00:00.000 AM | 1 | message
10/2/2019, 10:00:03.000 AM | 2 | message (last msg for this operation id)
10/2/2019, 10:00:00.000 AM | 3 | message
10/2/2019, 10:00:00.000 AM | 2 | message
10/2/2019, 10:00:15.000 AM | 3 | message (last msg for this operation id)
期望的输出：
timestamp | operation_id | message
---------------------------|--------------------------------------------------------
10/2/2019, 10:00:10.000 AM …