Athena UNLOAD and empty values
1
Im saving data to JSON using UNLOAD Athena command. Some of non-string fields are empty. UNLOAD command puts null's everywhere instead. Is there any way to tell Athena to skip serialization of a field if it is empty?
質問済み 7ヶ月前299ビュー
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When using the Amazon Athena UNLOAD command, it uses the default serializer LazySimpleSerDe. This serializer outputs empty values as Null, like you are experiencing, and cannot be changed.
One option is to specify each column in your select that you do not want to output to null and use a function to transform nulls. This would be instead of doing a SELECT *.
For example:
UNLOAD (SELECT col1, COALESCE(col2,'') FROM table)
TO 's3://my_athena_data_location/my_folder/'
WITH (format = 'JSON')
References:
回答済み 7ヶ月前
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