SQL FIRST() 函數(shù)

SQL FIRST() 函數(shù)

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　FIRST() 函數(shù)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;      

注釋：只有 MS Access 支持 FIRST() 函數(shù)。

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

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SQL Server 語法

SELECT TOP 1 column_name
FROM table_name
ORDER BY column_name ASC;  

實例

SELECT TOP 1 CustomerName FROM Customers                
ORDER BY CustomerID ASC;      

MySQL 語法

SELECT column_name FROM table_name                
ORDER BY column_name ASC                
LIMIT 1; 

實例

SELECT CustomerName FROM Customers               
ORDER BY CustomerID ASC                
LIMIT 1;   

Oracle 語法

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

實例

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

演示數(shù)據(jù)庫

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　在本教程中，我們將使用眾所周知的 Northwind 樣本數(shù)據(jù)庫。

　下面是選自 "Customers" 表的數(shù)據(jù)：

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 snabbk?p	Christina Berglund	Berguvsv?gen 8	Lule?	S-958 22	Sweden

SQL FIRST() 實例

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