The current documentation for width_bucket (
https://www.postgresql.org/docs/current/functions-math.html) does not mention if the range’s low and high are inclusive or exclusive.
Returns the number of the bucket in which operand falls in a histogram having count equal-width buckets spanning the range low to high. Returns 0 or count+1
I had assumed that both the low and high were inclusive but actually the low is inclusive while the high is exclusive.
For example:
SELECT width_bucket(0, 0, 1, 4)
returns 1, the first of 4 bins
SELECT width_bucket(1, 0, 1, 4)
returns 5, because the high was outside the exclusive bound of high = 1
Thank you!