friendlymatthew opened a new issue, #18825: URL: https://github.com/apache/datafusion/issues/18825
### Is your feature request related to a problem or challenge? Union arrays currently cannot be used in comparison operations with scalar values or other types. When attempting to filter or compare a union column against a constant value (e.g., `where union_column = 67`), datafusion fails during type coercion This prevents common filtering and selection ops on union-typed data. At work, we interact with a lot of JSON and accessing data with `->` returns Union types. Currently the following query will err: ```sql select * from records where json_val->'id' = 123 ``` ### Describe the solution you'd like - Write a `union_coercion` function that handles union-to-scalar and union-to-union type coercion, following the pattern established by other composite types like `struct_coercion` and `map_coercion` - Extend `comparison_coercion` to chain to `union_coercion` as part of its coercion attempts On the arrow-side, comparison kernel support for unions are being developed: - https://github.com/apache/arrow-rs/issues/8837 - https://github.com/apache/arrow-rs/issues/8881 ### Describe alternatives you've considered _No response_ ### Additional context _No response_ -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
