sql判断Email和用户名

sql语句判断Email格式和用户名中不能有特殊字符（用户名只包含字母、数字、下划线）的语句怎么写

SELECT  email_address
    FROM  email
    WHERE  REGEXP_LIKE (email_address,'[a-zA-Z0-9._%-]+@[a-zA-Z0-9._%-]+\.[a-zA-Z]{2,4}');

或者：


select id       , name       , email  from t_superheros  where regexp_like        (email        ,'^\w+(\.\w+)*+@\w+(\.\w+)+$');

SELECT
  EmailAddress, 
  CASE WHEN EmailAddress LIKE '%_@_%_.__%' 
            AND EmailAddress NOT LIKE '%[any obviously invalid characters]%' 
  THEN 'Could be' 
  ELSE 'Nope' 
  END Validates
FROM 
  Table