There are many times when our users want to query all the issues for the prior month or week and want to save that to a filter. The current model only allows that to be done on a fixed date basis. It would be nice to add the following two functions to JQL to make this easier to accomplish:
startOfLastMonth()
startOfLastWeek()

Maybe even the following as well:
startOfLastYear()

That way users can write queries like:
.... and created >= startOfLastMonth() and created < startOfMonth()

These would be very useful when doing metrics, and I would think would be very simple to implement.

Please consider adding these functions.

Thanks.