Custom query in Query Service using SQL?

Imho if you write queries you need to use SQL not PQL. What type of audience it would be? I assume batchhttps://developer.adobe.com/experience-platform-apis/references/segmentation/#operation/createAudience Create an audience then wait for next segment job or use flexible audience evaluation 

"conextual email attribute" you mean coming from the event?

@Silvio6 do you know why I cannot chosse AEP source? 

OMG ......Love you man! Do you know if in the campaigns it works the same? Any constraints in the journeys while changing the email?

In documentation there is an example: https://experienceleague.adobe.com/en/docs/journey-optimizer/using/configuration/primary-email-addresses#in-the-email-configuration In my env: 

I am during green field implementation of AEP and ATWould you ingest data into both AEP and AT or only AEP? 1. Only AEPNeed to share audience with AT and the choose every specific attribute  2. Both AEP and AT- can easily use Data Mart attributes in AT segmentation- new integration to keep an eye on...

Is AEP able to display on a product page:- count of how many people viewed/bought this specific product?It might be doable using Computed Attributes ....

I am a consultant, customers sometimes do like ask philosophical questions :)))

With Web SDK I can use 3rd party cookies enabled and then with multiple domains profiles should be merged?