描述
题目：对于申请参与比赛的用户，blog_url字段中url字符后的字符串为用户个人博客的用户名，现在运营想要把用户的个人博客用户字段提取出单独记录为一个新的字段，请取出所需数据。
示例：user_submit
| device_id | profile | blog_url |
| 2138 | 180cm,75kg,27,male | http:/ur/bisdgboy777 |
| 3214 | 165cm,45kg,26,female | http:/url/dkittycc |
| 6543 | 178cm,65kg,25,male | http:/ur/tigaer |
| 4321 | 171 cm,55kg,23,female | http:/url/uhksd |
| 2131 | 168cm,45kg,22,female | http:/url/sydney |
根据示例，你的查询应返回以下结果：
| device_id | user_name |
| 2138 | bisdgboy777 |
| 3214 | dkittycc |
| 6543 | tigaer |
| 4321 | uhsksd |
| 2131 | sydney |
示例1
输入：
drop table if exists user_submit; CREATE TABLE `user_submit` ( `id` int NOT NULL, `device_id` int NOT NULL, `profile` varchar(100) NOT NULL, `blog_url` varchar(100) NOT NULL ); INSERT INTO user_submit VALUES(1,2138,'180cm,75kg,27,male','http:/url/bisdgboy777'); INSERT INTO user_submit VALUES(1,3214,'165cm,45kg,26,female','http:/url/dkittycc'); INSERT INTO user_submit VALUES(1,6543,'178cm,65kg,25,male','http:/url/tigaer'); INSERT INTO user_submit VALUES(1,4321,'171cm,55kg,23,female','http:/url/uhsksd'); INSERT INTO user_submit VALUES(1,2131,'168cm,45kg,22,female','http:/url/sysdney');
输出：
2138|bisdgboy777 3214|dkittycc 6543|tigaer 4321|uhsksd 2131|sysdney
参考：
切割、截取、删除、替换
select
-- 替换法 replace(string, '被替换部分','替换后的结果')
-- device_id, replace(blog_url,'http:/url/','') as user_name
-- 截取法 substr(string, start_point, length*可选参数*)
-- device_id, substr(blog_url,11,length(blog_url)-10) as user_nam
-- 删除法 trim('被删除字段' from 列名)
-- device_id, trim('http:/url/' from blog_url) as user_name
-- 字段切割法 substring_index(string, '切割标志', 位置数（负号：从后面开始）)
device_id, substring_index(blog_url,'/',-1) as user_name
from user_submit;注意：本文归作者所有，未经作者允许，不得转载
