exec存储过程中，如果参数为空，如何返回空结果集？ （SQL Server）

Question

I am currently working with this code:

CREATE PROCEDURE Test 
    @char VARCHAR(MAX) = ____
AS
    SELECT * 
    FROM Table1 
    WHERE column ___  =  @char + _____

And I need to make it so that if the user executes the stored procedure without a value for the parameter, it should return an empty result set. And if they provide a value, then it returns the result set for that value provided.

How would I go about in filling in those blanks?

I figured out how to do it but it would require me to change the code so my way would be:

CREATE PROCEDURE Test 
    @char VARCHAR(MAX) = NULL
AS
    SELECT * 
    FROM Table1 
    WHERE column = ISNULL(@char, NULL)

I believe this way works, but the question wants me to do it their way, does anyone know how to do it with the way the question has it structured?

Thank you for any help!

Answer 1

---Try this it's Might work for you
-- SET @char NULL If it's '____' 

    DECLARE @char VARCHAR(MAX) = '____'

        IF @char ='____' 
        SET @char= NULL

        SELECT * 
        FROM Table1 
        WHERE column= @char