WITH data (date_from, date_to) AS (
    SELECT DATE'2015-01-01', DATE'2015-01-10' FROM DUAL UNION ALL
    SELECT DATE'2015-01-03', DATE'2015-01-11' FROM DUAL
)
SELECT
    min(date_from) date_from, max(date_to) date_to 
FROM (
    SELECT
        date_from, date_to,
        sum(merge) OVER (ORDER BY date_from) group_id
    FROM (
        SELECT
            date_from, date_to,
            case when date_from <= lag(date_to) OVER (ORDER BY date_from)
                 THEN 0
                 ELSE 1
            end as merge
        FROM data)
    ) intervals
GROUP BY group_id
ORDER BY min(intervals.date_from);

我的数据还包含较小的非重叠日期范围，被一个大的日期范围吞没。此解决方案不包括这种情况。例如：

WITH
  DATA (DATE_FROM, DATE_TO) AS
    (SELECT DATE '2015-01-01', DATE '2015-01-20' FROM DUAL
     UNION ALL
     SELECT DATE '2015-01-02', DATE '2015-01-04' FROM DUAL
     UNION ALL
     SELECT DATE '2015-01-05', DATE '2015-01-07' FROM DUAL
     UNION ALL
     SELECT DATE '2015-01-08', DATE '2015-01-10' FROM DUAL
     UNION ALL
     SELECT DATE '2015-01-11', DATE '2015-01-13' FROM DUAL)
  --=======================================================================
  SELECT MIN(DATE_FROM) DATE_FROM, MAX(DATE_TO) DATE_TO
    FROM (
           SELECT DATE_FROM, DATE_TO, SUM(MERGE) OVER (ORDER BY DATE_FROM) GROUP_ID
             FROM (SELECT DATE_FROM, DATE_TO, CASE WHEN DATE_FROM <= LAG(DATE_TO) OVER (ORDER BY DATE_FROM) THEN 0 ELSE 1 END AS MERGE FROM DATA)
         ) INTERVALS
GROUP BY GROUP_ID
ORDER BY MIN(INTERVALS.DATE_FROM)

输出将生成4行，即仅生成一行：

DATE_FROM   DATE_TO
2015/01/01  2015/01/20
2015/01/05  2015/01/07
2015/01/08  2015/01/10
2015/01/11  2015/01/13