SQL 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_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


 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


 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;