都不为空就一起输出吗? SELECT NVL(IP,DNS) FROM TABLE UNION SELECT NVL(DNS,IP) FROM TABLE
select decode(ip,null,dns,ip) ip,decode(dns,null,ip,dns) dns from 表A
一列:select nvl(IP,DNS) from A union select nvl(DNS,IP) from A;--------------------------- 两列: select decode(IP,null,DNS,IP) as IP, decode(DNS,null,IP,DNS) as DNS from A;
SELECT NVL(IP,DNS) FROM TABLE
UNION
SELECT NVL(DNS,IP) FROM TABLE
from A
union
select nvl(DNS,IP)
from A;---------------------------
两列:
select decode(IP,null,DNS,IP) as IP,
decode(DNS,null,IP,DNS) as DNS
from A;