Spark SQL datediff in seconds

问题:

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.

回答1:

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()