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SQL FIRST() 函数
SQL FIRST() 函数FIRST() 函数FIRST() 函数返回指定的列中第一个记录的值。SQL FIRST() 语法SELECT FIRST(column_name) FROM table_name;注释:只有 MS Access 支持 FIRST() 函数。SQL Server、MySQL 和 Oracle 中的 SQL FIRST() 工作区SQL Server 语法SELECT TOP 1 column_nameFROM table_nameORDER BY column_name ASC;实例SELECT TOP 1 name FROM WebsitesORDER BY id ASC;MySQL 语法SELECT column_name FROM table_nameORDER BY column_name ASCLIMIT 1;实例SELECT name FROM WebsitesORDER BY id ASCLIMIT 1;Oracle 语法SELECT column_name FROM table_nameORDER BY column_name ASCWHERE ROWNUM <=1;实例SELECT name FROM WebsitesORDER BY id ASCWHEREROWNUM <=1;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 || 6 | 百度 | https:
//www.baidu.com/ | 4 | CN || 7 | stackoverflow | http:
//stackoverflow.com/ | 0 | IND |+----+---------------+---------------------------+-------+---------+SQL FIRST() 实例下面的 SQL 语句选取 "Websites" 表的 "name" 列中第一个记录的值:实例SELECT name AS FirstSite FROM Websites LIMIT 1;执行以上 SQL 结果如下所示:
//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 || 6 | 百度 | https:
//www.baidu.com/ | 4 | CN || 7 | stackoverflow | http:
//stackoverflow.com/ | 0 | IND |+----+---------------+---------------------------+-------+---------+SQL FIRST() 实例下面的 SQL 语句选取 "Websites" 表的 "name" 列中第一个记录的值:实例SELECT name AS FirstSite FROM Websites LIMIT 1;执行以上 SQL 结果如下所示:
SQL FIRST() 函数