Easy MS SQL Server Solution Using RIGHT + LEN + PATINDEX
Code
# Code
```mssql []
SELECT user_id , email
FROM Users
WHERE RIGHT(email,4) = '.com' and LEN(email) - LEN(REPLACE(email,'@','')) = 1 and 
PATINDEX('%[^a-zA-Z0-9_]%@%',email) = 0 and PATINDEX('%@%[^a-zA-Z]%.com%',email) = 0
```
['Database', 'MS SQL Server']