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SQL LEN() 函数
SQL LEN() 函数LEN() 函数LEN() 函数返回文本字段中值的长度。SQL LEN() 语法SELECT LEN(column_name) FROM table_name;MySQL 中函数为 LENGTH():
SELECT LENGTH(column_name) FROM table_name;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 LEN() 实例下面的 SQL 语句从 "Websites" 表中选取 "name" 和 "url" 列中值的长度：实例SELECT name, LENGTH(url) as LengthOfURLFROM Websites;执行以上 SQL 输出结果如下：
SELECT LENGTH(column_name) FROM table_name;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 LEN() 实例下面的 SQL 语句从 "Websites" 表中选取 "name" 和 "url" 列中值的长度：实例SELECT name, LENGTH(url) as LengthOfURLFROM Websites;执行以上 SQL 输出结果如下：
SQL LEN() 函数
