How to write correct array string parameter for mysql query?
Use find_in_Set
Schema (MySQL v5.7)
CREATE TABLE group_of_id_s (id_s int ,`date`date);

INSERT INTO group_of_id_s VALUES(1,'2020-08-01'),(2,'2020-07-01');


delimiter //
CREATE PROCEDURE myproc (IN parameter TEXT)
       BEGIN
         SELECT id_s FROM group_of_id_s
         WHERE find_in_set(`date`, parameter) &gt; 0;
       END//
delimiter ;       


Query #1
CALL myproc(&quot;2020-08-01,2020-08-01,2020-08-02,2020-08-03,2020-08-04&quot;);

| id_s |
| ---- |
| 1    |


View on DB Fiddle