SparkSQL - 以分钟为单位的两个时间戳之间的差异

Question

我正在尝试将两个时间戳之间的分钟差异转换为MM/dd/yyyy hh:mm:ss AM/PM. 我刚开始使用 SparkSQL 并尝试使用datediff其他 SQL 语法支持的基本函数 Ie datediff(minute,start_time,end_time)，但这产生了错误：

org.apache.spark.sql.AnalysisException: cannot resolve '`minute`' given input columns: [taxisub.tpep_dropoff_datetime, taxisub.DOLocationID, taxisub.improvement_surcharge, taxisub.VendorID, taxisub.trip_distance, taxisub.tip_amount, taxisub.tolls_amount, taxisub.payment_type, taxisub.fare_amount, taxisub.tpep_pickup_datetime, taxisub.total_amount, taxisub.store_and_fwd_flag, taxisub.extra, taxisub.passenger_count, taxisub.PULocationID, taxisub.mta_tax, taxisub.RatecodeID]; line 1 pos 153;

似乎minutesparkSQL 的 datediff 不支持该参数。我目前的查询是：

spark.sqlContext.sql("Select to_timestamp(tpep_pickup_datetime,'MM/dd/yyyy hh:mm:ss') as pickup,to_timestamp(tpep_dropoff_datetime,'MM/dd/yyyy hh:mm:ss') as dropoff, datediff(to_timestamp(tpep_pickup_datetime,'MM/dd/yyyy hh:mm:ss'),to_timestamp(tpep_dropoff_datetime,'MM/dd/yyyy hh:mm:ss')) as diff from taxisub ").show()

我的结果是：

+-------------------+-------------------+----+
|             pickup|            dropoff|diff|
+-------------------+-------------------+----+
|2018-12-15 08:53:20|2018-12-15 08:57:57|   0|
|2018-12-15 08:03:08|2018-12-15 08:07:30|   0|
|2018-12-15 08:28:34|2018-12-15 08:33:31|   0|
|2018-12-15 08:37:53|2018-12-15 08:43:47|   0|
|2018-12-15 08:51:02|2018-12-15 08:55:54|   0|
|2018-12-15 08:03:47|2018-12-15 08:03:50|   0|
|2018-12-15 08:45:21|2018-12-15 08:57:08|   0|
|2018-12-15 08:04:47|2018-12-15 08:29:05|   0|
|2018-12-15 08:01:22|2018-12-15 08:12:15|   0|
+-------------------+-------------------+----+

datediff鉴于结果中的 0，我假设默认值是天数差异。我应该使用其他参数/​​函数来确定这两个时间戳之间的分钟差异吗？

提前致谢。

Answer 1

在 Spark sql 中有两种方法可以做到这一点。您将时间戳列转换为 bigint，然后减去并除以 60 是否可以直接转换为 unix_timestamp 然后减去并除以 60 以获得结果。我使用了上面数据框中的拾取和丢弃列。（在 pyspark/scala spark 中，bigint 很长）

spark.sqlContext.sql("""select pickup, dropoff, (unix_timestamp(dropoff)-unix_timestamp(pickup))/(60) as diff from taxisub""").show()

或者

spark.sqlContext.sql("""select pickup, dropoff, ((bigint(to_timestamp(dropoff)))-(bigint(to_timestamp(pickup))))/(60) as diff from taxisub""").show()

输出：

+-------------------+-------------------+------------------+
|             pickup|            dropoff|              diff|
+-------------------+-------------------+------------------+
|2018-12-15 08:53:20|2018-12-15 08:57:57| 4.616666666666666|
|2018-12-15 08:03:08|2018-12-15 08:07:30| 4.366666666666666|
|2018-12-15 08:28:34|2018-12-15 08:33:31|              4.95|
|2018-12-15 08:37:53|2018-12-15 08:43:47|               5.9|
|2018-12-15 08:51:02|2018-12-15 08:55:54| 4.866666666666666|
|2018-12-15 08:03:47|2018-12-15 08:03:50|              0.05|
|2018-12-15 08:45:21|2018-12-15 08:57:08|11.783333333333333|
|2018-12-15 08:04:47|2018-12-15 08:29:05|              24.3|
|2018-12-15 08:01:22|2018-12-15 08:12:15|10.883333333333333|
+-------------------+-------------------+------------------+