select to_char(TRUNC(sysdate-15),'yyyy-MM-dd') as '前15天' from dual
select to_char(TRUNC(sysdate+15),'yyyy-MM-dd') as '后15天' from dual
SELECT TRUNC(TRUNC(sysdate-15), 'MM') + ROWNUM - 1 FROM DUAL CONNECT BY ROWNUM <= TO_NUMBER(TO_CHAR(TRUNC(sysdate+15), 'dd'))