select round(decode(sum(te1 + te2), 0, 0, sum(te1) / sum(te1 + te2) * 100),
             2),
       ny
  from sg t
 where data not in (select data
                  from sg 
                minus
                select distinct t1.data
                  from kj t1, hl t2
                 where t1.data = t2.data
                   and qy = 'dba'
                   and jb = 'l'
                   and t1.hsj = 'qj'
                    or t1.fdf = 'ju')
   and ny between 200902 and 201106
 group by ny

------解决方案--------------------
探讨


有谁能告诉我如何查看执行计划吗？


------解决方案--------------------
这个语句有些问题

select round(decode(sum(te1+te2),0,0,sum(te1)/sum(te1+te2)*100),2),ny from sg t 
where data in 
(select distinct t1.data from kj t1,hl t2 
where t1.data =t2.data and qy='dba' and jb='l' and t1.hsj='qj' or t1.fdf='ju')
  and ny between 200902 and 201106 group by ny 
  1、红色标记：and和or并行用，只有and有效。这里你可能写出了一个逻辑错误，这回导致inlist列表很大。会影响性能
2、黄色 inlins 不用 distince排序。

最后你要评估取出的数据是全部，还是部分，如果是少部分，是否有索引。