将查询的结果生成到文件中：
set echo on            --是否显示执行的命令内容 
set feedback off       --是否显示 *   rows   selected 
set heading off        --是否显示字段的名称
set verify off         --是否显示替代变量被替代前后的语句。fil
set trimspool off      --去字段空格
set pagesize 1000      --页面大小
set linesize 50//linesize设定尽量根据需要来设定，大了生成的文件也大
define fil= 'e:/exp.txt'
prompt *** Spooling to &fil
spool &fil
select id||','||username||','||'"'||password||'"' from myuser;
spool off;

强行杀session：

SELECT DISTINCT '(' || s.sid || ') - ' || username AS "(session) - username",
o.kglnaobj FROM V$SESSION s, sys.x$kglob o, sys.x$kglpn p WHERE upper(o.kglnaobj) LIKE ('%P_CREATE_TABLE_ZJ_USER_INFO%') AND p.kglpnhdl = o.kglhdadr AND s.SADDR =

select spid, osuser, s.program
from v$session s,v$process p
where s.paddr=p.addr and s.sid in(53);

查看表空间信息:
select f.tablespace_name,a.total,u.used,f.free,round((u.used/a.total)*100) "% used",
  round((f.free/a.total)*100) "% Free"
  from
  (select tablespace_name, sum(bytes/(1024*1024)) total
       from dba_data_files group by tablespace_name) a,
  (select tablespace_name, round(sum(bytes/(1024*1024))) used
       from dba_extents group by tablespace_name) u,
  (select tablespace_name, round(sum(bytes/(1024*1024))) free
       from dba_free_space group by tablespace_name) f
WHERE a.tablespace_name = f.tablespace_name
and a.tablespace_name = u.tablespace_name;

查看回滚段信息：
select d.sql_text,a.name
from v$rollname a,v$transaction b,v$session c,v$sqltext d
where a.usn=b.xidusn and b.addr=c.taddr
and c.sql_address= d.address
and c.sql_hash_value=d.hash_value;