今晚一个令我自卑的sql调优问题

Question

今天调试一个sql语句，可以查询出来，且结果集是对的，但是开发组长让调优一下。
弄了很长时间，还是没有完成优化，
语句如下： select *
  from tb_core_settlement ts
 where ts.id in (select ins.jbpmobjectid
                   from processinstance ins
                  where ins.jbpmprocessid in
                        (select jti.procinst_
                           from jbpm_TaskInstance jti
                          where jti.token_ in
                                (select distinct taskinstan0_.TOKEN_
                                   from JBPM_TASKINSTANCE taskinstan0_,
                                        JBPM_POOLEDACTOR  pooledacto1_
                                  where (taskinstan0_.END_ is not null)
                                    and (taskinstan0_.PROCINST_ in
                                        (select taskinstan2_.PROCINST_
                                            from JBPM_TASKINSTANCE    taskinstan2_,
                                                 JBPM_PROCESSINSTANCE processins3_
                                           where taskinstan2_.PROCINST_ =
                                                 processins3_.ID_
                                             and (taskinstan2_.END_ is null)))
                                    and pooledacto1_.ACTORID_ =
                                        '8a9594e53227b459013227c1eff40065'
                                    and pooledacto1_.ID_ = any
                                 -- in
                                  (select pooledacto4_.POOLEDACTOR_
                                           from JBPM_TASKACTORPOOL pooledacto4_
                                          where taskinstan0_.ID_ =
                                                pooledacto4_.TASKINSTANCE_)
                                     or taskinstan0_.ACTORID_ =
                                        '8a9594e53227b459013227c1eff40065')
                            and jti.isSuspended_ != 1
                            and jti.isOpen_ = 1))语句很长且性能很低下
后来同事帮解决，语句如下，但是不清楚如何做的优化，而且看不明白如何从上面复杂的语句变为一段简洁sql语句，请sql高手帮分析，谢谢
select distinct ts.*
  from tb_core_settlement ts, processinstance ins, jbpm_TaskInstance jti
 where ts.id = ins.jbpmobjectid
   and ins.jbpmprocessid = jti.procinst_
   and jti.token_ in
       (select distinct taskinstan0_.TOKEN_
          from jbpm_TaskInstance taskinstan0_
         where taskinstan0_.ACTORID_ = '8a9594e53218f1a60132197c22c2045f'
           and jti.isSuspended_ != 1
           and jti.isOpen_ = 1)
百分感谢帮分析！！！

Answer 1

我不注重于其他，只想知道怎么从我那句sql会通过下面的那条sql实现，两个语句有差异么？

Answer 2

汗，这么多IN，优化余地太大了，用表连接不要用IN，

Answer 3

一部分已经大概看明白了，想再问下。select *
  from tb_core_settlement ts
 where ts.id in (select ins.jbpmobjectid
                   from processinstance ins
                  where ins.jbpmprocessid in
                        (select jti.procinst_
                           from jbpm_TaskInstance jti
                          where jti.token_ in
                                (select distinct taskinstan0_.TOKEN_
                                   from jbpm_TaskInstance taskinstan0_
                                  where taskinstan0_.ACTORID_ =
                                        '8a9594e531d615480131d651ed1400a5')
                            and jti.isSuspended_ != 1
                            and jti.isOpen_ = 1))这段sql的in可以优化为关联查询么，为何可以那样改？
还有就是里面的语句，比如select * from a,b where a.id = b.aid and a.name = b.aname or a.age = b.aage。这条语句的话是不是可以解释为select * from a,b where （a.id = b.aid and a.name = b.aname ）or a.age = b.aage