关于null,0,1排序问题

Question

某字段的值或null或0或1 
现在我想按1,0,null来排, 
可是order by aa desc 还是asc 
都达不到效果,desc把null排在了前面(null,1,0), asc又是(0,1,null)排,哪位高人有好的排法?
不考虑把字段属性加default 0,
尝试用case,when,then也未能实现

Answer 1

SQL> select * from t1;                                    IDX CNAME
--------------------------------------- ------------------------------------------------------------
                                      1 test
                                      1 test
                                      0 test
                                        test
                                      0 test
                                      1 test6 rows selectedSQL> select idx,cname from t1 order by decode(idx,1,2,0,1,0) desc;                                    IDX CNAME
--------------------------------------- ------------------------------------------------------------
                                      1 test
                                      1 test
                                      1 test
                                      0 test
                                      0 test
                                        test6 rows selected

Answer 2

SELECT * FROM t ORDER BY decode(a,NULL,-1,a) DESC;

Answer 3

order by aa desc nulls last 

Answer 4

oracle不熟啊,有这么方法可以用，多谢