ORACLE 时间段

--固定层数
SELECT * FROM DUAL CONNECT BY LEVEL < 10

--固定层数
SELECT LEVEL,SYSDATE+LEVEL FROM DUAL CONNECT BY LEVEL < (SYSDATE+10)-(SYSDATE);

结果图

有些人喜欢用rownum代替level。我不推荐使用rownum

请测试下面结果：

--获取日期时间段
SELECT TO_CHAR(TO_DATE('20190825','YYYYMMDD')+LEVEL-1,'YYYYMMDD') AS 日期时间段 FROM DUAL CONNECT BY LEVEL <= TO_DATE('20190901','YYYYMMDD')-TO_DATE('20190825','YYYYMMDD')

--获取月份时间段
SELECT TO_CHAR(ADD_MONTHS(TO_DATE('20180901','YYYYMMDD'),LEVEL-1),'YYYYMM') AS 月份时间段 FROM DUAL CONNECT BY LEVEL<= MONTHS_BETWEEN(TO_DATE('20190901','YYYYMMDD'),TO_DATE('20180901','YYYYMMDD'));

--获取年份时间段
SELECT TO_CHAR(ADD_MONTHS(TO_DATE('20150901','YYYYMMDD'),(LEVEL-1)*12),'YYYY') AS 年份时间段 FROM DUAL CONNECT BY LEVEL <= MONTHS_BETWEEN(TO_DATE('20190901','YYYYMMDD'),TO_DATE('20150901','YYYYMMDD'))/12;