I have the following query to find all subscribers that have not opened in the past 180 days:

Target Data extension has: SUBSCRIBER RELATIONSHIP ContactKey relates to Subscribers on Subscriber Key

all fields are nullable in target DE other than the Contact Key which is the primary key(only need the contact key and email address to pull into the target data extension)

Query validates and runs, yet no data populates the target DE?

Query:

SELECT distinct s.subscriberkey as ContactKey, e.EmailAddress as Email FROM _Sent s JOIN _subscribers e on s.subscriberkey=e.subscriberkey WHERE s.EventDate > dateadd(Day,-180,getdate()) AND s.subscriberkey NOT IN ( SELECT e.subscriberkey FROM _Open WHERE EventDate > dateadd(Day,-180,getdate()))