DotNetNuke Not Uniq Emails

Sometimes clients ask to make registration at the site with uniq emails only. It somehow prevents to appear duplicates of the users. But sometimes site is live already and have a lot of registered users, then it needs to find all users with not uniq emails in DB and to fix. It is possible with query like this:

SELECT UserID, UserName, FirstName, LastName, Email, DisplayName

FROM {databaseOwner}{objectQualifier}Users

WHERE Email IN

(

SELECT Email

FROM {databaseOwner}{objectQualifier}Users

GROUP BY Email

HAVING COUNT(Email)>1

);

Hope this helps!