oracle实现从当天回顾工作日前n天对应的具体工作日日期

SELECT day
FROM (
    SELECT 
        day,
        SUM(CASE WHEN is_zm = 'N' THEN 1 ELSE 0 END) 
            OVER (ORDER BY day DESC ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) as workday_count
    FROM work_day
    WHERE day <= TRUNC(SYSDATE)
)
WHERE workday_count = 10
AND ROWNUM = 1;