How can I find duplicated emails using Data Extensions or through Contact Builder? My SQL knowledge is pretty much none, and i want to know if there's a viable way to find these duplicate emails using other tools rather SQL. Appreciate all helpful ideas Thank you

  • You can’t avoid using SQL. And you would probably want to query not only data extensions, but also your all subscribers list - as this can contain multiple subscribers with same email address, and different subscriber keys Commented May 27 at 17:58
  • Appreciate the help. Can you provide some helpful articles/tips where i can look at and apply easily, please? Thank you once again Commented May 27 at 22:13

1 Answer 1


You could start by running this query:

top 100000 emailaddress, 
count(subscriberkey) as addresses 
from _listsubscribers 
group by emailaddress 
order by count(subscriberkey) desc

This will return the email addresses with most duplicate records in your All Subscribers.

You wrote, that you want to do this in your data extensions. This is not easily achievable, as you most probably have hundreds of data extensions in your SFMC account. Some of them might even have intentionally multiple records per each email address - making duplicates normal.

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