SQL FIRST() 函数

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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

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SQL Server 语法

SELECT TOP 1 column_name
FROM table_name
ORDER BY column_name ASC;

实例

SELECT TOP 1 CustomerName FROM Customers                
ORDER BY CustomerID ASC;

MySQL 语法

SELECT column_name FROM table_name                
ORDER BY column_name ASC                
LIMIT 1;

实例

SELECT CustomerName FROM Customers               
ORDER BY CustomerID ASC                
LIMIT 1;

Oracle 语法

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

实例

SELECT CustomerName FROM Customers                
ORDER BY CustomerID ASC                
WHERE ROWNUM <=1;

演示数据库

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在本教程中，我们将使用众所周知的 Northwind 样本数据库。

下面是选自 "Customers" 表的数据：

CustomerID	CustomerName	ContactName	Address	City	PostalCode	Country
1	Alfreds Futterkiste	Maria Anders	Obere Str. 57	Berlin	12209	Germany
2	Ana Trujillo Emparedados y helados	Ana Trujillo	Avda. de la Constitución 2222	México D.F.	05021	Mexico
3	Antonio Moreno Taquería	Antonio Moreno	Mataderos 2312	México D.F.	05023	Mexico
4	Around the Horn	Thomas Hardy	120 Hanover Sq.	London	WA1 1DP	UK
5	Berglunds snabbköp	Christina Berglund	Berguvsvägen 8	Luleå	S-958 22	Sweden

SQL FIRST() 实例

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下面的 SQL 语句选取 "Customers" 表的 "CustomerName" 列中第一个记录的值：

实例

SELECT FIRST(CustomerName) AS FirstCustomer FROM Customers;