andygrove opened a new issue, #16254: URL: https://github.com/apache/datafusion/issues/16254
### Describe the bug I have this csv file: ``` a,b x,NaN x,NaN x,NaN ``` With a simple select query, DF says there is only 1 distinct value for column b (which, I think is correct). ``` > select count(distinct b) from 'nan.csv'; +---------------------------+ | count(DISTINCT nan.csv.b) | +---------------------------+ | 1 | +---------------------------+ ``` However, in an aggregate query, DF says there are 3 distinct values: ``` > select a, count(distinct b) from 'nan.csv' group by 1 order by 1; +---+---------------------------+ | a | count(DISTINCT nan.csv.b) | +---+---------------------------+ | x | 3 | +---+---------------------------+ ``` This behavior seems inconsistent. I would expect the aggregate query to also report that there is one distinct value (in Spark, the behavior is consistent between the two queries). ### To Reproduce _No response_ ### Expected behavior _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: github-unsubscr...@datafusion.apache.org.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org
