关于查询速度问题！谢谢

Question

我有两个查询sql，一个查询的速度就很快，而另一个查询的非常慢，所查询出的数据都是大约4万条记录。想了一个上午也没有解决。哪位大哥帮帮我！谢谢
这个是快的
select t.login_user || '--' ||
       (select k.user_name from user_t k where k.user_id = t.login_user) login_user,
       t.tel,
       t.aux_time,
       t.aux_times,
       t.zd_disconnect,
       t.bd_disconnect,
       to_char(t.login_time, 'yyyy-mm-dd hh24:mi:ss') login_time,
       to_char(t.logout_time, 'yyyy-mm-dd hh24:mi:ss') logout_time,
       t.talk_time
  from seatstate_count_t t
 where 1 = 1
   and t.login_user not in ('0001', '0002', '0003')
   and t.login_time between
       to_date('2009-01-14 00:00', 'yyyy-mm-dd hh24:mi') and
       to_date('2010-04-14 23:59', 'yyyy-mm-dd hh24:mi')
 order by t.login_user, t.login_user, t.login_user
这个是慢的
select a.event_id,
       b.dept deptid,
       (select name from d_dept_tree_v t where t.deptid = b.dept) deptname,
       a.event_code,
       getdeptname(b.dept) receive_dept,
       a.receive_user,
       a.contact_tele,
       a.call_tele,
       (select code_value
          from d_event_type_v v1
         where v1.code_id = a.event_type) event_type,
       a.call_owner,
       caller,
       to_char(a.call_time, 'yyyy-mm-dd hh24:mi') call_time,
       a.place,
       a.event_content,
       v.code_id,
       v.code_value,
       f.*
  from event_t a,
       disposal_t b,
       (select t.event_id,
               nvl(t.other_type, 'other') other_type,
               nvl(t.other_type2, 'other1') other_type2
          from accident_info_t t) c,
       (select * from d_disposal_state_v) v,
       (select a.user_name, b.group_name, a.user_id, a.xh
          from user_t_history a, user_group_t b
         where b.group_code = a.group_code) f
 where a.last_disposal_id = b.disposal_id
   and a.event_id = c.event_id
   and a.event_id = b.event_id
   and b.state = v.code_id
   and a.receive_user = f.xh
   and a.call_time between
       to_date('2009-04-01 00:00:00', 'yyyy-mm-dd hh24:mi:ss') and
       to_date('2009-04-15 23:59:59', 'yyyy-mm-dd hh24:mi:ss')
   and b.dept in
       (53, 01, 0102, 0103, 0104, 0106, 02, 0202, 0203, 0204, 0206, 0207, 03, 0302, 0303, 04, 0402, 0403, 05, 0502, 0503, 0504, 0505, 0506, 0507, 0509, 06, 0602, 0603, 0604, 0605, 0607, 07, 0702, 0703, 0704, 0705, 0706, 08, 0802, 09, 0902, 0903, 0904, 10, 11, 12, 1202, 1203, 13, 14, 15, 16, 1602, 1604, 1605, 17, 18, 21, 22, 67, 91)
 order by a.call_time,
          b.state,
          decode(deptid,
                 '53',
                 '0001',
                 '01',
                 '001',
                 '0102',
                 '00102',
                 '0103',
                 '00103',
                 '0104',
                 '00104',
                 '0106',
                 '00106',
                 '02',
                 '002',
                 '0202',
                 '00202',
                 '0203',
                 '00203',
                 '0204',
                 '00204',
                 '0206',
                 '00206',
                 '0207',
                 '00207',
                 '03',
                 '003',
                 '0302',
                 '00302',
                 '0303',
                 '00303',
                 '04',
                 '004',
                 '0402',
                 '00402',
                 '0403',
                 '00403',
                 '05',
                 '005',
                 '0502',
                 '00502',
                 '0503',
                 '00503',
                 '0504',
                 '00504',
                 '0505',
                 '00505',
                 '0506',
                 '00506',
                 '0507',
                 '00507',
                 '0509',
                 '00509',
                 '06',
                 '006',
                 '0602',
                 '00602',
                 '0603',
                 '00603',
                 '0604',
                 '00604',
                 '0605',
                 '00605',
                 '0607',
                 '00607',
                 '07',
                 '007',
                 '0702',
                 '00702',
                 '0703',
                 '00703',
                 '0704',
                 '00704',
                 '0705',
                 '00705',
                 '0706',
                 '00706',
                 '08',
                 '008',
                 '0802',
                 '00802',
                 '09',
                 '009',
                 '0902',
                 '00902',
                 '0903',
                 '00903',
                 '0904',
                 '00904',
                 '12',
                 '01',
                 '1202',
                 '0102',
                 '1203',
                 '0103',
                 '16',
                 '02',
                 '1602',
                 '0202',
                 '1604',
                 '0204',
                 '1605',
                 '0205',
                 '21',
                 '03',
                 '22',
                 '04',
                 '13',
                 '05',
                 '14',
                 '06',
                 '17',
                 '07',
                 '18',
                 '08',
                 '15',
                 '09',
                 '11',
                 '10',
                 '10',
                 '11',
                 '67',
                 '2',
                 '91',
                 '3')

Answer 1

两个语句查出的记录数据差不多，查询的表不同，不具有可比性，
选出的数据量较大，第二个语句这么长的decode,还有in列表，
可以将decode中的代码放入字典表中。

Answer 2

查询计划贴出来看看
我感觉第2条肯定慢,DECODE消耗的语句就占用时间比较长

Answer 3

第一个是查询系统管理员的登录，登出信息。第二个是一个多条件的组合查询。   我这个问题可能太~~~那个了，   嗯  我试着把decode语句删除了  结果比以前的速度是快了。  但是需求就变了，唉 。我再看看啊！

Answer 4

哈哈  我知道拉  原来影响最大的是这句话  getdeptname(b.dept) receive_dept,
我改了。