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SQL MID() 函数
SQL MID() 函数MID() 函数MID() 函数用于从文本字段中提取字符。SQL MID() 语法SELECT MID(column_name,start[,length]) FROM table_name;参数描述column_name必需。要提取字符的字段。start必需。规定开始位置(起始值是 1)。length可选。要返回的字符数。如果省略,则 MID() 函数返回剩余文本。演示数据库在本教程中,我们将使用 RUNOOB 样本数据库。下面是选自 "Websites" 表的数据:+----+--------------+---------------------------+-------+---------+| id | name | url | alexa | country |+----+--------------+---------------------------+-------+---------+| 1 | Google | https:
//www.google.cm/ | 1 | USA || 2 | 淘宝 | https:
//www.taobao.com/ | 13 | CN || 3 | k88.net | http:
//www.k88.net/ | 4689 | CN || 4 | 微博 | http:
//weibo.com/ | 20 | CN || 5 | Facebook | https:
//www.facebook.com/ | 3 | USA || 7 | stackoverflow | http:
//stackoverflow.com/ | 0 | IND |+----+---------------+---------------------------+-------+---------+SQL MID() 实例下面的 SQL 语句从 "Websites" 表的 "name" 列中提取前 4 个字符:实例SELECT MID(name,1,4) AS ShortTitleFROM Websites;执行以上 SQL 输出结果如下:
//www.google.cm/ | 1 | USA || 2 | 淘宝 | https:
//www.taobao.com/ | 13 | CN || 3 | k88.net | http:
//www.k88.net/ | 4689 | CN || 4 | 微博 | http:
//weibo.com/ | 20 | CN || 5 | Facebook | https:
//www.facebook.com/ | 3 | USA || 7 | stackoverflow | http:
//stackoverflow.com/ | 0 | IND |+----+---------------+---------------------------+-------+---------+SQL MID() 实例下面的 SQL 语句从 "Websites" 表的 "name" 列中提取前 4 个字符:实例SELECT MID(name,1,4) AS ShortTitleFROM Websites;执行以上 SQL 输出结果如下:
SQL MID() 函数