在pyspark SQL中找到两个时间戳之间的差异

Question

Below table structure, you can notice the column name

cal_avg_latency = spark.sql("SELECT UnitType, ROUND(AVG(TIMESTAMP_DIFF(OnSceneDtTmTS, ReceivedDtTmTS, MINUTE)), 2) as latency, count(*) as total_count FROM `SFSC_Incident_Census_view` WHERE EXTRACT(DATE from ReceivedDtTmTS) == EXTRACT(DATE from OnSceneDtTmTS) GROUP BY UnitType ORDER BY latency ASC")

Error:

ParseException: "\nmismatched input 'FROM' expecting <EOF>(line 1, pos 122)\n\n== SQL ==\nSELECT UnitType, ROUND(AVG(TIMESTAMP_DIFF(OnSceneDtTmTS, ReceivedDtTmTS, MINUTE)), 2) as latency, count(*) as total_count FROM SFSC_Incident_Census_view WHERE EXTRACT((DATE FROM ReceivedDtTmTS) == EXTRACT(DATE FROM OnSceneDtTmTS)) GROUP BY UnitType ORDER BY latency ASC\n--------------------------------------------------------------------------------------------------------------------------^^^\n"

Error is in WHERE condition but even my TIMESTAMP_DIFF function not working

cal_avg_latency = spark.sql("SELECT UnitType, ROUND(AVG(TIMESTAMP_DIFF(OnSceneDtTmTS, ReceivedDtTmTS, MINUTE)), 2) as latency, count(*) as total_count FROM SFSC_Incident_Census_view  GROUP BY UnitType ORDER BY latency ASC")

Error :

AnalysisException: "Undefined function: 'TIMESTAMP_DIFF'. This function is neither a registered temporary function nor a permanent function registered in the database 'default'.; line 1 pos 27"

Answer 1

The error message seems pretty clear. Hive doesn't have a TIMESTAMP_DIFF function.

If your columns are already appropriately cast as a timestamp type, you can subtract them directly. Otherwise, you can cast them explicity, and take the difference:

SELECT ROUND(AVG(MINUTE(CAST(OnSceneDtTmTS AS timestamp) - CAST(ReceivedDtTmTS AS timestamp))), 2) AS latency

Answer 2

I have solve the problem using pyspark query.

from pyspark.sql import functions as F
import pyspark.sql.functions as func
timeFmt = "yyyy-MM-dd'T'HH:mm:ss.SSS"
timeDiff = (F.unix_timestamp('OnSceneDtTmTS', format=timeFmt)
        - F.unix_timestamp('ReceivedDtTmTS', format=timeFmt))
FSCDataFrameTsDF = FSCDataFrameTsDF.withColumn("Duration", timeDiff)
#convert seconds to minute and round the seconds for further use. 
FSCDataFrameTsDF = FSCDataFrameTsDF.withColumn("Duration_minutes",func.round(FSCDataFrameTsDF.Duration / 60.0))

Output: