MySQL存储过程变量为null

Question

请查看为什么在我打印变量以及将其插入表中时变量mpsId为空。当我单独运行select语句时，变量MPSId显示，但单独显示不显示

BLOCK1: begin

    declare done INT DEFAULT 0;
    declare gid BIGINT;
    declare activity_name VARCHAR(255) ;
    declare duration1 BIGINT;
    declare type_1 VARCHAR(255) ;
    declare mpsId VARCHAR(50);
    declare shop_activity_id BIGINT;
    declare start_date1 VARCHAR(100);
    declare curs CURSOR for select id, activityName, `duration`, `Type`, shopActivityId, MPSId, date_format(startDate, '%d-%m-%Y') from GanttTask where `Type` = 'Project';
    declare continue handler for not found set done :=1;
    open curs;
        LOOP1: loop
        fetch curs into gid, activity_name, duration1, type_1, shop_activity_id, mpsId, start_date1;
        if done = 1 then
            leave LOOP1;
        end if;
        select concat('MPS ID is ' ,mpsId);
        insert into app_fd_gantt_result (id, c_activityName, c_Type1, c_duration, `c_mpsId`, c_startDate, c_parent) VALUES (gid, activity_name, type_1, duration1, mpsId, start_date1, NULL);
        end loop LOOP1;
    close curs;
end BLOCK1

在创建存储过程之后，我在最后添加了此变量（我不认为这应该是一个问题）