I haven't queried data from the
_Subscribers data view before and faced with that issue. Please correct me if I did something in a wrong way.
At first, I created a temporary data extension with these fields:
SubscriberKey - Text - 254 - nullable
EmailAddress - EmailAddress - 254- nullable
Status - Text - 50 - nullable
A SQL query was created also and targeted to the temporary data extension above. The SQL looks like this:
SELECT SubscriberKey, EmailAddress, Status FROM _Subscribers WHERE SubscriberKey = '003O000001TzbzvIAB'
And run once. There is nothing returned into the data extension. I tried to remove the line
WHERE SubscriberKey = '003O000001TzbzvIAB', it returned 825 results into the data extension.
I also double checked in All subscribers list/Search/Subscriber Key is equal to 003O000001TzbzvIAB and and still found the subscriber.
(Note: I did the query from a Dev Business Unit)