oracle 时间分段查询

/*建表*/

create table test1(serviceid number,
callerno number,
begintime date,
endtime date

);

/*设置数据库时间格式*/

alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss';

/*某个时段查询*/

select to_date('2009-06-01 00:00:00', 'yyyy-mm-dd hh24:mi:ss') +  (n - 1) / 48 sec_begin,

       to_date('2009-06-01 00:00:00', 'yyyy-mm-ddhh24:mi:ss') + n / 48 sec_end,

       count(callerno) callnum, 

       nvl(sum(endtime - begintime),0) * 24 * 60 * 60 "calllength(s)"

       

from test1 t, (select rownum n from dual connect by level < = 48) integers

where t.begintime 
between

      to_date('2009-06-01 00:00:00', 'yyyy-mm-dd hh24:mi:ss') + (n - 1) / 48  

      and

      to_date('2009-06-01 00:00:00', 'yyyy-mm-dd hh24:mi:ss') + n / 48

      

group by n;

/*全天分段查询*/

select to_date('2009-06-01 00:00:00', 'yyyy-mm-dd hh24:mi:ss') + (n - 1) / 48 sec_begin,

        to_date('2009-06-01 00:00:00', 'yyyy-mm-ddhh24:mi:ss') + n / 48 sec_end,

        count(callerno) callnum,

        nvl(sum(endtime - begintime),0) * 24 * 60 * 60 "calllength(s)"

        

from test1 t 

  

  right join (select rownum n from dual connect by level < = 48) integers

  on t.begintime 

  between

        to_date('2009-06-01 00:00:00', 'yyyy-mm-dd hh24:mi:ss') + (n - 1) / 48 

        and

        to_date('2009-06-01 00:00:00', 'yyyy-mm-dd hh24:mi:ss') + n / 48

        

group by n;