关于一个不好处理的order by 有难度 请帮忙

Question

select * from table1 order by decode(time_to,'0-0','999',time_to) desc;

Answer 1

让0-0左边补0进行排序，这样就可以了！
select * from table1 order by lpad(time_to,7,'9') ;

Answer 2

select * from table1 order by decode(time_to,'0-0','999',time_to) desc;

Answer 3

对time_to = '0-0'做一下转换就好了^_^[code]
20:22:42 SQL> select * from t;       PID TIME_FROM            TIME_TO
---------- -------------------- --------------------
         8 2002-10              0-0
         8 2001-02              2002-09
         7 2001-10              2003-10
         7 2001-02              2002-09Elapsed: 00:00:00.01
20:22:49 SQL> select *
20:22:55   2  from t
20:22:56   3  order by decode(time_to,'0-0',null,time_to) desc nulls first
20:23:17   4  /       PID TIME_FROM            TIME_TO
---------- -------------------- --------------------
         8 2002-10              0-0
         7 2001-10              2003-10
         8 2001-02              2002-09
         7 2001-02              2002-09Elapsed: 00:00:00.00
20:23:17 SQL>
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