Randall Skelton <skelton(at)brutus(dot)uwaterloo(dot)ca> writes:
> Correction, I don't want to simply get the nth row, I want all rows
> that are divisible by n. Essentially, the timestamp is at a regular
> interval and I want a way of selecting rows at different sampling
> intervals.
Couldn't you code this as a WHERE test on the timestamp?
regards, tom lane