select a.owner||',"'||a.object_name||'",'||a.object_id||','||
to_char(a.created,'yyyy-mm-dd hh24:mi:ss')||','||a.status
from dba_objects a,(select rownum rn from dual connect by rownum<=20) b;
我知道是 dba_objects和 dual的某些行做的联合,问题是:
里面的||' 是做什么用的?
to_char(a.created,'yyyy-mm-dd hh24:mi:ss')||','||a.status
from dba_objects a,(select rownum rn from dual connect by rownum<=20) b;
我知道是 dba_objects和 dual的某些行做的联合,问题是:
里面的||' 是做什么用的?
常量字符串是要用单引号包起来的比如说下面的吧
a.owner||',"'||a.object_name
就是把a.owner和,"连起来 再和a.object_name连起来