oracle 大批量数据sql优化

在同事的帮助下学习到的优化方法：    

   select /*+ rule*/t1.Pid,t1.Pname,
         decode(t2.Pstatus,
                '5',
                '5 - 未审核',
                '7',
                '7 - 删除',
                '9',
                '9 - 已审核') Pstatus,
        
          from t1,
               t2
         where 1 = 1
           AND t1.Psdate >= '20100907'
           and t1.Pedate <= '20100907'
           and t1.Pid(+) = t2.Pid

同时发现：外连接的时候（+）有些情况下 比left join 效率高些