统计网页跳出率的问题

procedure sp_searchanalytics（
          p_start_date         in date,
          p_end_date           in date,
          p_keyword            in varchar2,
          p_domain             in varchar2,
          p_return             out cur_retrieve
)
as
begin
open p_return for
select t.page_url_no_domain_no_para,
       t.view_count,
       （
       select count（distinct guid)
       from s_tvsn_analytics_history
       where page_url_no_domain_no_para = t.page_url_no_domain_no_para
       and  （p_start_date is null or open_date >= p_start_date)
       and  （p_end_date is null or open_date <= p_end_date)
       and  （p_domain  is null or domain = p_domain)
       ) user_count,
       --以下这个select效率非常低，是算跳出次数的
       （
       select count（*) 
       from s_tvsn_analytics_history tah
       where page_url_no_domain_no_para = t.page_url_no_domain_no_para
       and  （p_start_date is null or open_date >= p_start_date)
       and  （p_end_date is null or open_date <= p_end_date)
       and  （p_domain  is null or domain = p_domain)
       and （
           select count（*) 
           from s_tvsn_analytics_history
           where guid = tah.guid
           and   ip = tah.ip
           and   ref_url = tah.page_url
           and   open_date > tah.open_date
           ) = 0
       ) exit_count 
from （
select page_url_no_domain_no_para, 
       sum（1) view_count
from s_tvsn_analytics_history
where  （p_start_date is null or open_date >= p_start_date)
and    （p_end_date is null or open_date <= p_end_date)
and    （p_keyword is null or page_url_no_para like '%' || p_keyword || '%')
and    （p_domain  is null or domain = p_domain)
group by page_url_no_domain_no_para) t;
end sp_searchanalytics;