We are currently running a Campaign that will last 10 days. We are now looking to send another email to this same data extension but want it to go to only people who have received the first email. How can I filter the data extension to allow me to see and send to contacts that have received this certain email.
You can use one of these two options:
1- On the Tracking tab, you can see the jobID of the email you sent. When you enter it, you can click on the number of people who got the email to export them as a .csv file. You can put those people into a data extension and send to them.
2- You can query based on the jobID from SendLog as pkharries said. You can see the example below:
SELECT EmailAddress, SubscriberKey FROM _Sent WHERE JobID = YOURJOBID