sql数据库查询数据量太大查不出来?

select dt,num,count(*) from
    (SELECT
        CONCAT(YEAR (create_time),'年',WEEK(create_time),'周') dt,
        COUNT(1) AS num
    FROM mail_record202108
    GROUP BY dt,`to` ORDER BY WEEK(create_time))t1
group by num order by dt,num;