pyspark.sql.functions.nvl# pyspark.sql.functions.nvl(col1, col2)[source]# Returns col2 if col1 is null, or col1 otherwise. New in version 3.5.0. Parameters col1Column or str col2Column or str Examples >>> df = spark.createDataFrame([(None, 8,), (1, 9,)], ["a", "b"]) >>> df.select(nvl(df.a, df.b).alias('r')).collect() [Row(r=8), Row(r=1)]