JackieTien97 opened a new issue, #17939: URL: https://github.com/apache/iotdb/issues/17939
### Search before asking - [x] I searched in the [issues](https://github.com/apache/iotdb/issues) and found nothing similar. ### Motivation ### Motivation IoTDB already provides frequency-domain analysis capabilities in the tree model through UDFs such as `fft`/`ifft` in `library-udf`. However, users who work with the table model currently do not have an equivalent built-in or library-level way to run FFT/DFT analysis directly in SQL. For table-model workloads, frequency-domain analysis is useful for scenarios such as vibration monitoring, rotating machinery diagnosis, signal periodicity analysis, anomaly detection, and sensor data preprocessing. Users should be able to calculate Fourier transform results over a time-ordered numeric column, optionally partitioned by device/tag columns, without switching back to the tree model or exporting data to external tools. ### Solution Add FFT and DFT support for the IoTDB table model. A possible design is to provide table-model functions such as `fft` and `dft` that can process a numeric column ordered by time and return frequency-domain results. The exact SQL syntax can be discussed, but the function should support table-model usage patterns, for example: ```sql SELECT * FROM TABLE( fft( TABLE( SELECT time, device_id, value FROM vibration WHERE time >= 0 AND time < 10000 ) PARTITION BY device_id ORDER BY time ) ); ### Solution _No response_ ### Alternatives _No response_ ### Are you willing to submit a PR? - [ ] I'm willing to submit a PR! -- 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]
