mysql怎么把日期转换成对应的星期几

查出来的日期怎么转换成对应的星期几

上面数据SQL语句如下:

SELECT
    t2.all_day AS `日期`
FROM
    (
        SELECT
            @rownum :=@rownum + 1 AS NO,
            DATE_ADD(
                '2021-02-22',
                INTERVAL @rownum DAY
            ) AS all_day
        FROM
            (SELECT @rownum := -1) r_init,
            agency
    ) t2
LEFT JOIN (select * from agency where agencytype=1) as agency ON (
    t2.all_day = DATE(agency.createTime)
)LEFT JOIN old ON (
    t2.all_day = DATE(old.createTime)
)LEFT JOIN (select * from agency where agencytype=2) as shequ  ON (
    t2.all_day = DATE(shequ.createTime)
)
WHERE
    t2.all_day >= '2021-02-22'
AND t2.all_day <= '2021-02-28'
GROUP BY
    t2.all_day;
    
   

有哪位大神帮帮我!!!!