DROP FUNCTION :
This statement could be used to remove an existing user-defined function.
Syntax :
DROP FUNCTION [ IF EXISTS ] schema_name.function_name;
Example –
Let’s consider Geeks is the function you want to delete then use the following syntax as follows.
DROP FUNCTION Geeks;
To drop more than one user-defined functions, use below syntax :
DROP FUNCTION [IF EXISTS] schema_name.function_name1, schema_name.function_name2, ...;
Parameters :
-
IF EXISTS –
IF EXISTS parameter is optional used to drop the function only if it exists. In case of removing a non-existing function without using the IF EXISTS option, SQL Server will throw an error. -
schema_name –
The schema_name is an optional parameter. The schema_name defines the name of the schema to which the user-defined function belongs. -
function_name –
The function_name is the name of the function that will be removed.
Notes :
If there are constraints like CHECK or DEFAULT in the function, the DROP FUNCTION statement will return error.
Example –
Lets us create a function that calculates discount from amount, list, and percentage :
Creating “Geek.discount_amount” function –
CREATE FUNCTION Geek.discount_amount ( @amount INT, @list DEC(10,2), @percentage DEC(4,2) ) RETURNS DEC(10,2) AS BEGIN RETURN @quantity * @amount * @percentage END
To drop the function, you can use the following SQL query given below.
DROP FUNCTION IF EXISTS Geek.discount_amount;