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https://issues.apache.org/jira/browse/SPARK-31657?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17103670#comment-17103670
]
Hyukjin Kwon commented on SPARK-31657:
--
That's already fixed in the master:
{code]
>>> df1 = spark.sql("SELECT 1 as a")
>>> df1.limit(1).write.mode("OVERWRITE").option("Header",
>>> True).csv("data/test/csv")
>>> spark.read.option("Header", True).csv("data/test/csv").show()
+---+
| a|
+---+
| 1|
+---+
>>> df1.limit(0).write.mode("OVERWRITE").option("Header",
>>> True).csv("data/test/csv")
>>> spark.read.option("Header", True).csv("data/test/csv").show()
+---+
| a|
+---+
+---+
{code}
at SPARK-26208
> CSV Writer writes no header for empty DataFrames
>
>
> Key: SPARK-31657
> URL: https://issues.apache.org/jira/browse/SPARK-31657
> Project: Spark
> Issue Type: Bug
> Components: Input/Output
>Affects Versions: 2.4.1
> Environment: Local pyspark 2.41
>Reporter: Furcy Pin
>Priority: Minor
>
> When writing a DataFrame as csv with the Header option set to true,
> the header is not written when the DataFrame is empty.
> This creates failures for processes that read the csv back.
> Example (please notice the limit(0) in the second example):
> ```
>
> {code:java}
> Welcome to
> __
> / __/__ ___ _/ /__
> _\ \/ _ \/ _ `/ __/ '_/
> /__ / .__/\_,_/_/ /_/\_\ version 2.4.1
> /_/
> Using Python version 2.7.17 (default, Nov 7 2019 10:07:09)
> SparkSession available as 'spark'.
> >>> df1 = spark.sql("SELECT 1 as a")
> >>> df1.limit(1).write.mode("OVERWRITE").option("Header",
> >>> True).csv("data/test/csv")
> >>> spark.read.option("Header", True).csv("data/test/csv").show()
> +---+
> | a|
> +---+
> | 1|
> +---+
> >>>
> >>> df1.limit(0).write.mode("OVERWRITE").option("Header",
> >>> True).csv("data/test/csv")
> >>> spark.read.option("Header", True).csv("data/test/csv").show()
> ++
> ||
> ++
> ++
> {code}
>
> Expected behavior:
> {code:java}
> >>> df1.limit(0).write.mode("OVERWRITE").option("Header",
> >>> True).csv("data/test/csv")
> >>> spark.read.option("Header", True).csv("data/test/csv").show()
> +---+
> | a|
> +---+
> +---+{code}
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