Oracle SQL查询缺少月份

SELECT TO_CHAR(ADD_MONTHS(start_date, LEVEL-1), 'YYYY-MM') AS month
FROM (
  SELECT DATE '2022-01-01' AS start_date, DATE '2022-12-31' AS end_date
  FROM dual
)
CONNECT BY LEVEL <= MONTHS_BETWEEN(end_date, start_date) + 1;

SELECT month, COUNT(t.date_column) AS count
FROM (
  -- 原始查询
  SELECT date_column
  FROM table_name
) t
RIGHT JOIN (
  -- 生成的日期序列
  SELECT TO_CHAR(ADD_MONTHS(start_date, LEVEL-1), 'YYYY-MM') AS month
  FROM (
    SELECT DATE '2022-01-01' AS start_date, DATE '2022-12-31' AS end_date
    FROM dual
  )
  CONNECT BY LEVEL <= MONTHS_BETWEEN(end_date, start_date) + 1
) d ON TO_CHAR(t.date_column, 'YYYY-MM') = d.month
GROUP BY month
ORDER BY month;