MySQL stored procedure selects return invalid values

Question

I noticed that the select statement inside my stored procedure always returns the same value, regardless of the parameter with which I call my stored procedure. Here is the code:

DELIMITER $$
CREATE PROCEDURE TEST(IN id INT)
BEGIN
  DECLARE x INT DEFAULT 0;
  select id;
    SELECT paper_id
    INTO x
    FROM Paper
    WHERE ID = id
    limit 1;
    select x;
END$$

x always returns the same value no matter what identifier I call the test with. I noticed that the x value is always the paper_id value in the front row of my Paper table.

However, if I run the same query outside the stored procedure, I get the expected value.

What happens inside a stored procedure that distorts this value?

Answer 1

MySQL, , WHERE ID = id " , " ?

, .