Spark SQL datediff 以秒为单位 [英] Spark SQL datediff in seconds

问题描述

我有以下代码:

table.select(datediff(table.col("Start Time"), table.col("End Time"))).show()

<块引用>

日期格式为 2016-05-19 09:23:28 (YYYY-MM-DD HH:mm:SS)

函数 datediff 计算天数差异.但我想以秒为单位.

解决方案

您可以使用 unix_timestamp() 函数将日期转换为秒.

import org.apache.spark.sql.functions._//对于 $ 符号列//Spark 2.0导入 spark.implicits._table.withColumn(date_diff",(unix_timestamp($"Start Time") - unix_timestamp($"End Time"))).展示()

(根据评论)

UDF 将秒数转换为 HH:mm:ss

sqlContext.udf.register(sec_to_time", (s: Long) =>((s/3600L) + ":" + (s/60L) + ":" + (s % 60L)))//现在使用注册的UDFtable.withColumn(date_diff",sec_to_time(unix_timestamp($"Start Time") - unix_timestamp($"End Time"))).展示()

I've got following code:

table.select(datediff(table.col("Start Time"), table.col("End Time"))).show()

Date format is 2016-05-19 09:23:28 (YYYY-MM-DD HH:mm:SS)

Function datediff calculate the difference in days. But I would like to have the difference in seconds.

解决方案

You can use unix_timestamp() function to convert date to seconds.

import org.apache.spark.sql.functions._

//For $ notation columns // Spark 2.0
import spark.implicits._

table.withColumn("date_diff", 
   (unix_timestamp($"Start Time") - unix_timestamp($"End Time"))
).show()

Edit:(As per comment)

UDF to covert Seconds to HH:mm:ss

sqlContext.udf.register("sec_to_time", (s: Long) => 
   ((s / 3600L) + ":" + (s / 60L) + ":" + (s % 60L))
)

//Use registered UDF now
table.withColumn("date_diff", 
   sec_to_time(unix_timestamp($"Start Time") - unix_timestamp($"End Time"))
).show()

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