oracle SQL确定以月为单位的连续期间

WITH monthly_sales AS (
    SELECT 
        TO_CHAR(sale_date, 'YYYY-MM') AS sale_month,
        SUM(amount) AS total_sales
    FROM sales
    GROUP BY TO_CHAR(sale_date, 'YYYY-MM')
),
ranked_months AS (
    SELECT 
        sale_month,
        total_sales,
        RANK() OVER (ORDER BY sale_month) AS rnk
    FROM monthly_sales
)
SELECT 
    rm1.sale_month AS start_month,
    rm2.sale_month AS end_month,
    rm1.total_sales + rm2.total_sales AS combined_sales
FROM ranked_months rm1
JOIN ranked_months rm2 ON rm1.rnk + 1 = rm2.rnk
ORDER BY rm1.sale_month;

SELECT 
    TO_CHAR(ADD_MONTHS(TO_DATE('2023-12', 'YYYY-MM'), LEVEL - 1), 'YYYY-MM') AS month
FROM dual
CONNECT BY LEVEL <= 3; -- 输出2023-12, 2024-01, 2024-02