SQL> select sysdate,to_date('1-1-2006','dd-mm-yyyy'),
2 case when sysdate > to_date('1-1-2006','dd-mm-yyyy') then sysdate
3 else to_date('1-1-2006','dd-mm-yyyy')
4 end
5 from dual;SYSDATE TO_DATE('1-1-2006','DD-MM-YYYY CASEWHENSYSDATE>TO_DATE('1-1-2
----------- ------------------------------ ------------------------------
2006-8-25 8 2006-1-1 2006-8-25 8:13:46SQL>
SQL> select sysdate,to_date('1-1-2006','dd-mm-yyyy'),
2 case when sysdate > to_date('1-11-2006','dd-mm-yyyy') then sysdate
3 else to_date('1-11-2006','dd-mm-yyyy')
4 end
5 from dual;SYSDATE TO_DATE('1-1-2006','DD-MM-YYYY CASEWHENSYSDATE>TO_DATE('1-11-
----------- ------------------------------ ------------------------------
2006-8-25 8 2006-1-1 2006-11-1SQL>
2 case when sysdate > to_date('1-1-2006','dd-mm-yyyy') then sysdate
3 else to_date('1-1-2006','dd-mm-yyyy')
4 end
5 from dual;SYSDATE TO_DATE('1-1-2006','DD-MM-YYYY CASEWHENSYSDATE>TO_DATE('1-1-2
----------- ------------------------------ ------------------------------
2006-8-25 8 2006-1-1 2006-8-25 8:13:46SQL>
SQL> select sysdate,to_date('1-1-2006','dd-mm-yyyy'),
2 case when sysdate > to_date('1-11-2006','dd-mm-yyyy') then sysdate
3 else to_date('1-11-2006','dd-mm-yyyy')
4 end
5 from dual;SYSDATE TO_DATE('1-1-2006','DD-MM-YYYY CASEWHENSYSDATE>TO_DATE('1-11-
----------- ------------------------------ ------------------------------
2006-8-25 8 2006-1-1 2006-11-1SQL>
要不就是这个时间范围内确实无记录