Converting timeZones

Hey, i am storing for each document a DateTime field in UTC timezone,
I want to group in cycles of times but in varied timezones (format e.g. GMT-08:00 , GMT+01:00 , …).
I’ve seen the Date functions for N1QL.
specifically: MILLIS_TO_ZONE_NAME(expression, tz_name [, fmt ]) which Converts the UNIX time stamp to a string in the named time zone, but what is the “named time zone” ? how do i convert the time from UTC to other timezone using the format i mentioned?
in MySQL i would do something like this :
GROUP BY UNIX_TIMESTAMP(CONVERT_TZ(dateTime, ‘GMT+02:00’’))/(cycle * 3600)"
How can i do something equivalent in N1QL?
In addition if i’m doing such a grouping in N1QL, how much would it slow down my query?
Thanks for the helpers.

Hi,

The zone name is the common name of the time zone, e.g. PDT or EST or UTC.

Otherwise, it is taken from https://en.wikipedia.org/wiki/List_of_tz_database_time_zones and https://golang.org/pkg/time/#Location .