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 语法
SELECT TOP 1 column_name FROM table_name
ORDER BY column_name ASC;SQL SERVER top查询示例
SELECT TOP 1 order_id FROM orders
ORDER BY order_amount ASC;
MySQL 语法
SELECT column_name FROM table_name
ORDER BY column_name ASC
LIMIT 1;MySQL limit查询示例
SELECT order_id FROM orders
ORDER BY order_amount ASC
LIMIT 1;
Oracle 语法
SELECT column_name FROM table_name
ORDER BY column_name ASC
WHERE ROWNUM <=1;Oracle rownum查询示例
SELECT name FROM Websites
ORDER BY id ASC
WHERE ROWNUM <=1;
演示数据库
在本教程中，我们将使用 yuanbian 样本数据库。
下面是选自 "orders" 表的数据：
+----------+--------------+----------+--------------+----------------+---------------------+
| order_id | order_no | goods_id | order_amount | order_quantity | create_date |
+----------+--------------+----------+--------------+----------------+---------------------+
| 1 | 201503120001 | 10 | 1000 | 10 | 2015-03-12 09:00:04 |
| 2 | 201503120002 | 12 | 1300 | 12 | 2015-03-12 17:23:10 |
| 3 | 201503130001 | 11 | 2400 | 22 | 2015-03-13 10:30:12 |
| 4 | 201503130002 | 12 | 2500 | 15 | 2015-03-13 11:00:05 |
| 5 | 201503130003 | 10 | 1400 | 15 | 2015-03-13 14:54:00 |
| 6 | 201503140001 | 12 | 2100 | 12 | 2015-03-14 11:34:00 |
+----------+--------------+----------+--------------+----------------+---------------------+
SQL FIRST() 示例
下面的 SQL 语句选取 "orders" 表的 "order_amount" 金额最大的一条的记录：
SELECT *
FROM orders
ORDER BY order_amount
LIMIT 1;执行以上 SQL 结果如下所示：
+----------+--------------+----------+--------------+----------------+---------------------+
| order_id | order_no | goods_id | order_amount | order_quantity | create_date |
+----------+--------------+----------+--------------+----------------+---------------------+
| 1 | 201503120001 | 10 | 1000 | 10 | 2015-03-12 09:00:04 |
+----------+--------------+----------+--------------+----------------+---------------------+
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