如何使用pyspark对SQL Server表进行分区，其中分区列是整数，但是是日期格式(20170101到20200306)？

from pyspark.sql import SparkSession
from pyspark.sql.functions import col

spark = SparkSession.builder \
    .appName("Partitioning SQL Server table with PySpark") \
    .getOrCreate()

df = spark.read \
    .format("jdbc") \
    .option("url", "jdbc:sqlserver://<server>:<port>;databaseName=<database>") \
    .option("dbtable", "<table>") \
    .option("user", "<username>") \
    .option("password", "<password>") \
    .load()

df = df.withColumn("partition_column", col("date_column").cast("integer"))

df.write \
    .format("jdbc") \
    .option("url", "jdbc:sqlserver://<server>:<port>;databaseName=<database>") \
    .option("dbtable", "<table>") \
    .option("user", "<username>") \
    .option("password", "<password>") \
    .option("partitionColumn", "partition_column") \
    .option("lowerBound", 20170101) \
    .option("upperBound", 20200306) \
    .option("numPartitions", 10) \
    .mode("overwrite") \
    .save()