修改用户定义函数

适用于：SQL ServerAzure SQL 数据库Azure SQL 托管实例

可以使用 SQL Server Management Studio 或 Transact-SQL 在 SQL Server 中修改用户定义函数。 按如下所述修改用户定义函数将不会更改函数的权限，并且也不会影响任何依赖的函数、存储过程或触发器。

限制和局限

ALTER FUNCTION 不能用于执行以下任何操作：

• 将标量值函数更改为表值函数，反之亦然。

• 将内联函数更改为多语句函数，反之亦然。

• 将 Transact-SQL 函数更改为 CLR 函数，反之亦然。

权限

需要对函数或架构具有 ALTER 权限。 如果函数指定用户定义类型，则需要对该类型具有 EXECUTE 权限。

使用 SQL Server Management Studio

1. 对于要修改的函数，选择包含该函数的数据库旁的加号。

2. 选择“可编程性”文件夹旁的加号。

3. 对于要修改的函数，选择包含该函数的文件夹旁的加号：

   • Table-valued Function

   • 标量值函数

   • Aggregate 函数

4. 右键单击要修改的函数，然后单击“修改”。

5. 在查询窗口中，对 ALTER FUNCTION 语句进行必要的更改。

6. 在“文件”菜单上，选择“保存”以保存 table_name。

使用 Transact-SQL

1. 在“对象资源管理器”中，连接到数据库引擎的实例。

2. 在标准栏上，选择“新建查询” 。

3. 将以下示例复制粘贴到查询窗口中，然后选择“执行”。

   下面的代码示例将更改一个标量值函数。

   -- Scalar-Valued Function
   USE [AdventureWorks2022]
   GO
   ALTER FUNCTION [dbo].[ufnGetAccountingEndDate]()
   RETURNS [datetime]
   AS
   BEGIN
       RETURN DATEADD(millisecond, -2, CONVERT(datetime, '20040701', 112));
   END;
   

   下面的代码示例将更改一个表值函数。

   -- Table-Valued Function
   USE [AdventureWorks2022]
   GO
   ALTER FUNCTION [dbo].[ufnGetContactInformation](@PersonID int)
   RETURNS @retContactInformation TABLE
   (
       -- Columns returned by the function
       [PersonID] int NOT NULL,
       [FirstName] [nvarchar](50) NULL,
       [LastName] [nvarchar](50) NULL,
       [JobTitle] [nvarchar](50) NULL,
       [BusinessEntityType] [nvarchar](50) NULL
   )
   AS
   -- Returns the first name, last name, job title and business entity type for the specified contact.
   -- Since a contact can serve multiple roles, more than one row may be returned.
   BEGIN
   IF @PersonID IS NOT NULL
   BEGIN
        IF EXISTS(SELECT * FROM [HumanResources].[Employee] e
        WHERE e.[BusinessEntityID] = @PersonID)
        INSERT INTO @retContactInformation
             SELECT @PersonID, p.FirstName, p.LastName, e.[JobTitle], 'Employee'
             FROM [HumanResources].[Employee] AS e
             INNER JOIN [Person].[Person] p ON p.[BusinessEntityID] = e.[BusinessEntityID]
             WHERE e.[BusinessEntityID] = @PersonID;
   
        IF EXISTS(SELECT * FROM [Purchasing].[Vendor] AS v
        INNER JOIN [Person].[BusinessEntityContact] bec ON bec.[BusinessEntityID] = v.[BusinessEntityID]
        WHERE bec.[PersonID] = @PersonID)
        INSERT INTO @retContactInformation
             SELECT @PersonID, p.FirstName, p.LastName, ct.[Name], 'Vendor Contact'
             FROM [Purchasing].[Vendor] AS v
             INNER JOIN [Person].[BusinessEntityContact] bec ON bec.[BusinessEntityID] = v.[BusinessEntityID]
             INNER JOIN [Person].ContactType ct ON ct.[ContactTypeID] = bec.[ContactTypeID]
             INNER JOIN [Person].[Person] p ON p.[BusinessEntityID] = bec.[PersonID]
             WHERE bec.[PersonID] = @PersonID;
   
        IF EXISTS(SELECT * FROM [Sales].[Store] AS s
        INNER JOIN [Person].[BusinessEntityContact] bec ON bec.[BusinessEntityID] = s.[BusinessEntityID]
        WHERE bec.[PersonID] = @PersonID)
        INSERT INTO @retContactInformation
             SELECT @PersonID, p.FirstName, p.LastName, ct.[Name], 'Store Contact'
             FROM [Sales].[Store] AS s
             INNER JOIN [Person].[BusinessEntityContact] bec ON bec.[BusinessEntityID] = s.[BusinessEntityID]
             INNER JOIN [Person].ContactType ct ON ct.[ContactTypeID] = bec.[ContactTypeID]
             INNER JOIN [Person].[Person] p ON p.[BusinessEntityID] = bec.[PersonID]
             WHERE bec.[PersonID] = @PersonID;
   
        IF EXISTS(SELECT * FROM [Person].[Person] AS p
        INNER JOIN [Sales].[Customer] AS c ON c.[PersonID] = p.[BusinessEntityID]
        WHERE p.[BusinessEntityID] = @PersonID AND c.[StoreID] IS NULL)
        INSERT INTO @retContactInformation
             SELECT @PersonID, p.FirstName, p.LastName, NULL, 'Consumer'
             FROM [Person].[Person] AS p
             INNER JOIN [Sales].[Customer] AS c ON c.[PersonID] = p.[BusinessEntityID]
             WHERE p.[BusinessEntityID] = @PersonID AND c.[StoreID] IS NULL;
        END
   RETURN;
   END;
   

另请参阅

• ALTER FUNCTION (Transact-SQL)