SELECT RIGHT(Email, LEN(Email) - CHARINDEX('@', email)) as emaildomain ,
COUNT(Email) as EmailCount
FROM [Your data extension]
WHERE LEN(Email) > 0
GROUP BY RIGHT(Email, LEN(Email) - CHARINDEX('@', email))
SELECT RIGHT(Email, LEN(Email) - CHARINDEX('@', email)) as emaildomain ,
COUNT(Email) as EmailCount
FROM [Your data extension]
WHERE LEN(Email) > 0
GROUP BY RIGHT(Email, LEN(Email) - CHARINDEX('@', email))