题解|

SELECT
    job_id,
    boss_id,
    company_id
FROM
    (
        SELECT
            job_id,
            boss_id,
            company_id,
            job_city
        FROM
            job_info
        WHERE
            YEAR (post_time) >= 2021
        UNION
        SELECT
            job_id,
            boss_id,
            company_id,
            job_city
        FROM
            job_info
        WHERE
            job_city = '上海'
    ) t
ORDER BY
    job_city ASC