紧急求一个SQL的写法：关于decode或case when；

Question

select decode(substr(id,1,1),1,'a',2,'a','') a,decode(substr(id,1,2),33,'bb',44,'bb','') b,decode(subtr(id,1,3),555,'ccc',666,'ccc','') c form table;

Answer 1

select decode(substr(id,1,1),'1','a','2','a','') || decode(substr(id,1,2),'33','bb','44','bb','') || decode(subtr(id,1,3),'555','ccc','666','ccc','') form yourtable;
如果你的id是数值型的话，就用to_char(id)替换id

Answer 2

赫赫，楼上的把一个字段变成3个字段拉
select decode(substr(id,1,1),1,'a',2,'a',
　　　　　(decode(substr(id,1,2),33,'bb',44,'bb',
　　　　　　　(decode(subtr(id,1,3),555,'ccc',666,'ccc',''))))
from tablename;
 

Answer 3

呵呵，sorry!!SQL> select decode(substr(555,1,1),1,'a',2,'a',(decode(substr(555,1,2),33,'bb',44,'bb',(decode(subst
r(555,1,3),555,'ccc',666,'ccc',''))))) from dual;DEC
---
ccc

Answer 4

原来substr()可以直接对数值操作啊，又学了一招

Answer 5

为什么不自己去查查decode函数的用法?