I'm using Marketing Cloud Connect and have synced across the Salesforce Contact object, which becomes a data extension. I have another data extension that I send related information to and I want to have the two data extensions relate on sharing the Salesforce Contact ID as a primary key, so I can combine all the fields in these two data extensions into one.
My target data extension has two columns that are not nullable - the primary key (Id, which is the Salesforce Contact ID) and Email. I'm not sending a null value to either column (I'm only sending null values to nullable columns), but I'm still getting the error message.
My query is as follows:
FROM Contact_Salesforce c
INNER JOIN PROFILE_DATA p ON c.Id=p.Contact_ID
WHERE C.SyncToMarketingCloud__c = 'TRUE'