alamb opened a new issue, #20135:
URL: https://github.com/apache/datafusion/issues/20135

   Other systems  support "metadata" columns when querying datasources. These 
metadata columns do not exist in the underlying data source but instead are 
related to the source
   
   Common examples:
   * Row number
   * File name
   * Row Group Number (parquet)
   
   ## DataBricks
   
   It appears DataBricks / spark represents this concept as a struct column 
`_metadata` column with multiple fields
   https://docs.databricks.com/aws/en/ingestion/file-metadata-column
   
   ```sql
   SELECT
       *
       ,_metadata
       ,_metadata.file_path
       ,_metadata.file_name
       ,_metadata.file_modification_time
   FROM
       json.`/path/to/table/data`
   ```
   
   
   Related tickets for adding similar metadata features to DataFusion:
   - [ ] https://github.com/apache/datafusion/issues/13975
   - [ ] https://github.com/apache/datafusion/issues/15173


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