如何在MSQL中TRIM电子邮件只留下没有重复的域（只有1个域）

I have Email column in my MSQL server and I need to trim the emails to only leave domains. So everything on the left side of @ including "@" needs to go away. At the same time I only need 1 domain so like no duplicates.. I have Email column in my MSQL server and I nee