连接2025年和2026年两个子表

SELECT
    t1.job,
    t1.year_mon AS first_year_mon,
    t1.cnt AS first_year_cnt,
    t2.year_mon AS second_year_mon,
    t2.cnt AS second_year_cnt
FROM
    (
        SELECT
            job,
            DATE_FORMAT (date, '%Y-%m') AS year_mon,
            MONTH(date) AS mon,
            SUM(num) AS cnt
        FROM
            resume_info
        WHERE
            YEAR (date) = '2025'
        GROUP BY
            job,
            year_mon, mon
    ) t1
JOIN(
        SELECT
            job,
            DATE_FORMAT (date, '%Y-%m') AS year_mon,
            MONTH(date) AS mon,
            SUM(num) AS cnt
        FROM
            resume_info
        WHERE
            YEAR (date) = '2026'
        GROUP BY
            job,
            year_mon, mon
    ) t2
WHERE
    t1.job = t2.job and t1.mon = t2.mon
ORDER BY
    first_year_mon DESC,
    job DESC

分别查询出2025年和2026年需要的数据，再将这两个表使用内连接连起来，连接条件一是job，二是mon（月份）。需要注意的是，如果mon的连接条件改为MONTH(t1.year_mon) = MONTH(t2.year_mon)，查询结果显示为空，搞不太清楚原因。难道是连接的条件中只能使用各表中已经存在的属性？