如果注册的用户数达到一定程度,我们可以在数据库(数据库培训 数据库认证 )查询语句对其进行统计。
以下SQL(SQL Server培训 mySQL培训 )语句能够统计出带某种类型后缀的email邮件注册量最大,及其排行顺序。
SELECT suffix_email, COUNT(suffix_email) AS email_count
FROM (SELECT SUBSTRING(email, CHARINDEX('@', email), 100) AS suffix_email
FROM user_table) temp_table
GROUP BY suffix_email
HAVING (COUNT(suffix_email) > 5)
ORDER BY email_count DESC
某网站对此排名后,发现排名前15的邮箱如下:
@163.com
@126.com
@sina.com
@yahoo.com.cn
@sohu.com
@hotmail.com
@tom.com
@21cn.com
@263.com
@vip.sina.com
@yahoo.com
@163.net
@qq.com
@gmail.com
@eyou.com |