KSQL事件合并 - 根据时间戳组合单个流的事件

Question

我正在尝试将多个事件从单个输入流组合到使用KSQL分组的单个输出事件中。我还希望输出事件包含一个输入事件的平均值，尽管这并不是严格的Nessersay，并且更适合。

输入流：温度

event1: {location: "hallway", value: 23, property_Id: "123", timestamp: "1551645625878"} 
event2: {location: "bedroom", value: 21, property_Id: "123", timestamp: "1551645625878"}
event3: {location: "kitchen", value: 20, property_Id: "123", timestamp: "1551645625878"}
event4: {location: "hallway", value: 19, property_Id: "123", timestamp: "9991645925878"} 
event5: {location: "bedroom", value: 18, property_Id: "123", timestamp: "9991645925878"}
event6: {location: "kitchen", value: 18, property_Id: "123", timestamp: "9991645925878"}

（所需）输出流：

event1:
{
    "property_id": "123",
    "timestamp": "1551645625878",
    "average_temperature": 21,   
    "temperature": [
        {
            "location": "hallway",
            "value": 23
        },
        {
            "location": "bedroom",
            "value": 21
        },
        {
            "location": "kitchen",
            "value": 20
        }
    ]
}
event2:
{
    "property_id": "123",
    "timestamp": "9991645925878",
    "average_temperature": 18,   
    "temperature": [
        {
            "location": "hallway",
            "value": 19
        },
        {
            "location": "bedroom",
            "value": 18
        },
        {
            "location": "kitchen",
            "value": 18
        }
    ]
}

据我所知，这是不可能使用KSQL的，任何人都可以确认吗？

Answer 1

正确，您当前无法在KSQL中执行此操作。截至v5.1/2019年3月，KSQL可以阅读但不能构建，嵌套对象：https：//github.com/confluentinc/ksql/ssues/2147（如果需要的话，请访问/注释）

）

您可以使用以下类型进行平均计算：

SELECT timestamp, SUM(value)/COUNT(*) AS avg_temp 
  FROM input_stream 
  GROUP BY timestamp;