Latest web development tutorials

SQL FIRST() 函數

FIRST() 函數

FIRST() 函數返回指定的列中第一個記錄的值。

SQL FIRST() 語法

SELECT FIRST(column_name) FROM table_name;

註釋:只有MS Access支持FIRST()函數。


SQL Server、MySQL 和Oracle 中的SQL FIRST() 工作區

SQL Server 語法

SELECT TOP 1 column_name FROM table_name
ORDER BY column_name ASC;

實例

SELECT TOP 1 name FROM Websites
ORDER BY id ASC;

MySQL 語法

SELECT column_name FROM table_name
ORDER BY column_name ASC
LIMIT 1;

實例

SELECT name FROM Websites
ORDER BY id ASC
LIMIT 1;

Oracle 語法

SELECT column_name FROM table_name
ORDER BY column_name ASC
WHERE ROWNUM <=1;

實例

SELECT name FROM Websites
ORDER BY id ASC
WHERE ROWNUM <=1;


演示數據庫

在本教程中,我們將使用w3big 樣本數據庫。

下面是選自"Websites" 表的數據:

+----+--------------+---------------------------+-------+---------+
| id | name         | url                       | alexa | country |
+----+--------------+---------------------------+-------+---------+
| 1  | Google       | https://www.google.cm/    | 1     | USA     |
| 2  | 淘宝          | https://www.taobao.com/   | 13    | CN      |
| 3  | 本教程      | http://www.w3big.com/    | 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() 實例

下面的SQL 語句選取"Websites" 表的"name" 列中第一個記錄的值:

實例

SELECT name AS FirstSite FROM Websites LIMIT 1;

執行以上SQL 結果如下所示: