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SQL Server FAQ - "ALTER FUNCTION" - Modifying Existing Functions
(Continued from previous topic...)
How To Modify an Existing User Defined Function?
If you find a mistake in an existing function previously created,
you can drop (delete) it and create it again correctly.
But dropping a function may affect other database objects who are depending
on this function.
So the best way to correct a mistake in an existing function
is to use the "ALTER FUNCTION" statement as shown in the following tutorial example:
-- Modifying an existing function
ALTER FUNCTION Sundays()
DECLARE @date DATETIME;
DECLARE @count INT;
SET @date = '2006-12-31';
SET @count = 0;
WHILE DATEPART(YEAR, @date) < 2008 BEGIN
SET @date = DATEADD(DAY, 1, @date);
IF DATENAME(WEEKDAY, @date) = 'Sunday'
SET @count = @count + 1;
Command(s) completed successfully.
Do you know what correction has been made on this function?
(Continued on next topic...)
- What Are User Defined Functions?
- What Are the Differences between User Defined Functions and Stored Procedures?
- How To Create a Simple User Defined Function?
- How To Use User Defined Functions in Expressions?
- How To List All User Defined Functions in the Current Database?
- How To Drop an Existing User Defined Function?
- How To Generate CREATE FUNCTION Script on an Existing Function?
- How To Get the Definition of a User Defined Function Back?
- How To Modify an Existing User Defined Function?
- How To Create User Defined Functions with Parameters?
- How To Provide Values to User Defined Function Parameters?
- Can You Pass Expressions to Function Parameters?
- How To Provide Default Values to Function Parameters?
- How Many Categories of Functions based Their Return Modes?
- How Many Ways to Create Table-Valued Functions?
- How To Create an Inline Table-Valued Function?
- How To Create an Multi-Statement Table-Valued Function?