mysql - Mysql子串

Question

大家好，我正在尝试迁移到新的邮件服务器，所以我想编写 Mysql 脚本以返回如下表，然后将结果导出为 CSV 文件 sql 语句，如下所示

`select email,clear,email AS domain from postfix_users `

我想在域名之前对@和@符号本身之前的任何字符进行子串化，任何想法都会有很大帮助

mysql> select email,clear,email AS domain from postfix_users ;

+---------------------------+--------+---------------------------+
| email                     | clear  | domain                    |
+---------------------------+--------+---------------------------+
| user@domain.tld           | passw  | user@domain.tld           |
+---------------------------+--------+---------------------------+

Answer 1

您可以使用 LOCATE 来查找 @ 的位置：

 LOCATE('@',email)

所以要找到域：

SELECT CASE 
    WHEN LOCATE('@',email) = 0 THEN ''
    ELSE SUBSTRING(email,LOCATE('@',email)+1)
    END as Domain
FROM YourTable