%pyspark

from pyspark.sql import SQLContext, Row
import sys
from pyspark.sql.window import Window
import pyspark.sql.functions as func

#Load the data
aquery = "(SELECT serial_number, min(date_time) min_date_time from schema.table where serial_number in ('abcdefg','1234567') group by serial_number) as minDates"

dfMinDates = sqlContext.read.format('jdbc').options(url='jdbc:postgresql://dadadadaaaredshift.amazonaws.com:5439/idw?tcpKeepAlive=true&ssl=true&sslfactory=org.postgresql.ssl.NonValidatingFactory?user=user&password=password', dbtable=aquery).load()
dfMinDates.show()

%pyspark

aquery = "(SELECT serial_number, min(date_time) min_date_time from schema.table where serial_number in ('abcdefg','1234567') group by serial_number) as minDates"

dfMinDates = spark.read.jdbc("jdbc:postgresql://dadadadaaaredshift.amazonaws.com:5439/idw?tcpKeepAlive=true&ssl=true&sslfactory=org.postgresql.ssl.NonValidatingFactory?user=user&password=password", dbtable=aquery).load()
dfMinDates.show()