I'm having a similar issue in Azure with MS-SQL Server Datawarehouse (DWH)

Eventhough I have set the target column to nvarchar(4000) on MS SQL Server DWH

This is the code:

spark.conf.set(
"spark.sql.parquet.writeLegacyFormat", "true")
dwDF.write.format("com.databricks.spark.sqldw")
    .option("url", sqlDwUrlSmall)
    .option("dbtable", TableName)
    .option( "forward_spark_azure_storage_credentials","True")
    .option("tempdir", tempDir)
    .mode("overwrite")
    .save()

I get the following error.

-
com.microsoft.sqlserver.jdbc.SQLServerException:
HdfsBridge::recordReaderFillBuffer - Unexpected error encountered filling
record reader buffer: HadoopSqlException: String or binary data would be
truncated. [ErrorCode = 107090] [SQLState = S0001]