bug: Median() truncates integers #19536

Great catch. I looked into it, and it seems like it's wrapping around due to integer overflow while taking the average of the middle two values (since the count is even).

low: [-85], high: -56, median: 57 datatype: Int8

-85 + -56 = -141 -> wraparound to 115
Then 115 / 2 -> 57.5 -> 57 (truncated due to integer type)

What's our desired behavior in this case? We could promote to a larger datatype to perform the calculation. Also is it intentional to return the value as a truncated integer instead of a float?

Originally posted by @petern48 in #19278 (comment)

The overflow part was fixed in #19322, but the truncation issue remains. Other databases seem to return a float: #19322 (comment)