Cursor only returning null values

Question

I have the following code (it is not finished yet I am only testing if the cursor is working for now). whenever I select the contents from the cursor, I only get null-values even though there are values in the table.

delimiter //
create procedure get_hr_bp()
begin
    declare done int default false;
    declare hr, sbp, dbp, new_hr, new_sbp, new_dbp numeric(3,0);
    declare cur cursor for select hr, sbp, dbp from patient;
    DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET done = true;
    
    open cur;
    read_loop: loop
        fetch cur into hr, sbp, dbp;
        select hr, sbp, dbp;
        
        
        if done then
            leave read_loop;
        end if;
        
    end loop;
    close cur;
    
end//
delimiter ;

Answer 1

You are using same variables names hr, sbp, dbp which are also your column names.

create procedure get_hr_bp()
begin
    declare done int default 0;
    declare new_hr, new_sbp, new_dbp numeric(3,0);
    declare cur cursor for select hr, sbp, dbp from patient;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;
    
    open cur;
    read_loop: loop
        fetch cur into new_hr, new_sbp, new_dbp;
        select new_hr, new_sbp, new_dbp;
        
        if done then
            leave read_loop;
        end if;

    end loop;
    close cur;
end;