一条sql语句优化的问题？

Question

select a.*,
(select max(decode(wjsymc, 'DW', wjsyz, null)) from epdm_bgwd_sy b where a.ttachment_journal_id=b.ttachment_journal_id) DW,
(select max(decode(wjsymc, 'ND', wjsyz, null)) from epdm_bgwd_sy b where a.ttachment_journal_id=b.ttachment_journal_id) ND,
(select max(decode(wjsymc, 'KTXM', wjsyz, null)) from epdm_bgwd_sy b where a.ttachment_journal_id=b.ttachment_journal_id) KTXM,
(select max(decode(wjsymc, 'GQ', wjsyz, null)) from epdm_bgwd_sy b where a.ttachment_journal_id=b.ttachment_journal_id) GQ,
(select max(decode(wjsymc, 'SJCXS', wjsyz, null)) from epdm_bgwd_sy b where a.ttachment_journal_id=b.ttachment_journal_id) SJCXS,
(select max(decode(wjsymc, 'SJDW', wjsyz, null)) from epdm_bgwd_sy b where a.ttachment_journal_id=b.ttachment_journal_id) SJDW,
(select max(decode(wjsymc, 'BXR', wjsyz, null)) from epdm_bgwd_sy b where a.ttachment_journal_id=b.ttachment_journal_id) BXR
from CD_ATTACHMENT_JOURNAL a where a.flid='003'如上sql，CD_ATTACHMENT_JOURNAL表中搜索出的信息要和epdm_bgwd_sy表搜索出行转列的数据合起来，有更好的方法吗？epdm_bgwd_sy表中有外键ttachment_journal_id，对应CD_ATTACHMENT_JOURNAL表中的主键。

Answer 1

select a.*, b.dw, b.nd, b.ktxm, b.gq, b.sjcxs, b.sjdw, b.bxr
  from CD_ATTACHMENT_JOURNAL a,
       (select ttachment_journal_id,
               max(decode(wjsymc, 'DW', wjsyz, null)) DW,
               max(decode(wjsymc, 'ND', wjsyz, null)) ND,
               max(decode(wjsymc, 'KTXM', wjsyz, null)) KTXM,
               max(decode(wjsymc, 'GQ', wjsyz, null)) GQ,
               max(decode(wjsymc, 'SJCXS', wjsyz, null)) SJCXS,
               max(decode(wjsymc, 'SJDW', wjsyz, null)) SJDW,
               max(decode(wjsymc, 'BXR', wjsyz, null)) BXR
          from epdm_bgwd_sy
         group by ttachment_journal_id) b
 where a.ttachment_journal_id = b.ttachment_journal_id(+)
   and a.flid = '003'
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