Attempting to run eval using value from min row returned by stats

[hzane]

I have a list of events with columns such as:
type,event_time,event_id,create_date

My objective is to find the lowest event_time and subtract the create date to pop out a calculated value, called here "ttn".

index=events 
type=notification 
|stats min(event_time) as init_time by event_id
|eval ttn = init_time - create_date

It seems so close! If I change create_date to a number, that works. I was experimenting with appendpipe but to no avail.
This is my first week using Splunk and figuring out how to combine stats and eval in this manner is going to help immensely.

Thank you.

[hzane · Accepted solution]

I ended up getting the desired result by nesting my eval statement inside the stats clause.

stats min(eval(event_time-create_date)) as ttn by tid

Pretty easy. Now if I can get these joins to work I will be home free!