Hi folks!

Sandra de Jong,
1. You could create a calculated attribute that returns the timestamp of when the ticket was assigned to this group:

IF ([Changes - Field name]="group_id") AND ([Changes - Previous value]!=[Ticket group] AND [Changes - Previous value]!=NULL) 
THEN [Update - Timestamp]
ENDIF

Then make a time difference between that timestamp and now in a calculated metric:

DATE_DIFF(NOW(),[your attribute],"nb_of_hours")

I would recommend testing the result of this metric on a couple of tickets before trusting it blindly to make sure it works as expected.

You can find more information about the DATE_DIFF functions in this article if you want to adapt it to your needs:

Explore functions reference

2. You can just use NULL to exclude or include all possible values. For instance:

IF ([Changes - Field name]="Your field")
AND ([Changes - Previous value] != NULL) AND ([Changes - New value] = NULL)
THEN VALUE(Field changes time (min))
ENDIF

Basically, we measure the time for which the ticket field did not have a NULL value. Once again, please test this metric for a couple of tickets to make sure it works according to your expectations.

Zaryab Khan, I cannot see a workaround for reporting on this during business hours. The initial metric Field changes time (min)) only uses calendar hours. We cannot even create a calculated metric as a workaround, since the functions that measure time cannot exclude specific ranges of hours:

Explore functions reference

I am sorry I could not provide better news.

Jordan Means, I think this is doable. You could create a calculated attribute using the DATE_FIRST function to capture the timestamp of the first time the status changes from Open to something else. Then, you could create a calculated metric that measures the time between the ticket creation and the timestamp returned by your attribute. Something like:

DATE_DIFF([your calculated attribute],[Ticket created - Timestamp],"nb_of_minutes")

You can find more information about the DATE_FIRST function and the DATE_DIFF functions in those articles:

I hope this helps!