SQL查询以查找具有相同电子邮件域的最大计数

Question

I have a email id column which stores the full email ID. I want to get the maximum count based on the domain ie @gmail.com,@xyz.com Seems like in GROUP BY clause we cannot apply any wildcards which will only consider the domain from the full email address.

Answer 1

For Mysql

SELECT SUBSTRING_INDEX(EMail.EMail, '@', -1) AS `Email Domain`, COUNT(*)
FROM EMail
GROUP BY SUBSTRING_INDEX(EMail.EMail, '@', -1)

with data example

SELECT SUBSTRING_INDEX(EMail.EMail, '@', -1) AS `Email Domain`, COUNT(*)
FROM
  (
  select 'tuhin@gmail.com' as EMail
  UNION
    SELECT 'tuhin@yahoo.com'
    union
    select 'abc@xyz.com'
    union
      select 'hin@gmail.com'
  ) as EMail

  GROUP BY SUBSTRING_INDEX(EMail.EMail, '@', -1)

For SQL server

SELECT RIGHT(Email, LEN(Email) - CHARINDEX('@', email)) Domain ,
COUNT(Email) EmailCount
FROM   dbo.email
WHERE  LEN(Email) > 0
GROUP BY RIGHT(Email, LEN(Email) - CHARINDEX('@', email))
ORDER BY EmailCount DESC