timsaucer opened a new issue, #688: URL: https://github.com/apache/datafusion-python/issues/688
**Describe the bug** When no window frame is specified in the python implementation, we default to unbounded preceeding to current row. If we are to follow [PostgreSQL implementation ](https://www.postgresql.org/docs/current/tutorial-window.html#:~:text=When%20ORDER%20BY%20is%20omitted%20the%20default%20frame%20consists%20of%20all%20rows%20in%20the%20partition.) then we should set this value when `order_by` is specified and otherwise default to unbounded preceeding to unbounded following. **To Reproduce** ``` from datafusion import SessionContext, WindowFrame, col, lit, functions as F import pyarrow as pa ctx = SessionContext() # create a RecordBatch and a new DataFrame from it batch = pa.RecordBatch.from_arrays( [pa.array([1.0, 10.0, 20.0])], names=["a"], ) df = ctx.create_dataframe([[batch]]) window_frame = WindowFrame("rows", None, None) df = df.select(col("a"), F.window("avg", [col("a")]).alias('no_frame'), F.window("avg", [col("a")], window_frame=window_frame).alias('with_frame')) df.show() ``` Produces: ``` DataFrame() +------+--------------------+--------------------+ | a | no_frame | with_frame | +------+--------------------+--------------------+ | 1.0 | 1.0 | 10.333333333333334 | | 10.0 | 5.5 | 10.333333333333334 | | 20.0 | 10.333333333333334 | 10.333333333333334 | +------+--------------------+--------------------+ ``` **Expected behavior** When `order_by` is not specified, default to unbounded preceeding to unbounded following. **Additional context** The offending line of code appears to be here: https://github.com/apache/datafusion-python/blob/main/src/functions.rs#L230 -- 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]
