问如何使用火花流计算卡夫卡过去25天的流数据均值和方差

EN

val sparkConf = new SparkConf().setAppName("StreamCount")
    val ssc = new StreamingContext(sparkConf, Seconds(2))
    //update the time according to your need

    // Create direct kafka stream with brokers and topics
    val topicsSet = topics.split(",").toSet
    val kafkaParams = Map[String, String]("metadata.broker.list" -> brokers)
    val messages = KafkaUtils.createDirectStream[String, String, StringDecoder, StringDecoder](
      ssc, kafkaParams, topicsSet)

    // Get the lines, and timestamp data along with the float values


    SELECT    float_number
FROM      [YourTable]
WHERE     [YourDate] BETWEEN DATEADD(DAY, DATEDIFF(DAY, 0, GETDATE()), 0) + '11:00' AND DATEADD(DAY, DATEDIFF(DAY, 0, GETDATE()), 0) + '12:00'
//store it to a data frame

df.select(avg($"float_number")).show()