日期:2014-05-17 浏览次数:20953 次
--1. 构建测试表test id 范围为 0 -- 178 
SQL> create table test (id) as select trunc(dbms_random.value(0,179)) from dual connect by level < 10000 ;
Table created.
--2. 构建范围表range_ 
SQL> create table range_ ( begin_ number , end_ number , id number) ;
Table created.
SQL> insert into range_ values (0,27,1) ;
1 row created.
SQL> insert into range_ values (27,48,2) ;
1 row created.
SQL> insert into range_ values (48,96,3) ;
1 row created.
SQL> insert into range_ values (96,111,4) ;
1 row created.
SQL> insert into range_ values (111,178,5) ;
1 row created.
SQL> commit ;
Commit complete.
SQL> select * from range_ order by id ;
    BEGIN_       END_         ID
---------- ---------- ----------
         0         27          1
        27         48          2
        48         96          3
        96        111          4
       111        178          5
--目标 根据 范围表 range_ 的列 begin_ end_ 统计 test 表中的数据分布情况 
--目标结果集举例: 
    BEGIN_       END_         ID   COUNT
---------- ---------- ---------- -------
         0         27          1    2000
        27         48          2    1999  
        48         96          3    2001
        96        111          4    1888
       111        178          5    2111
  select r.*,
         (select count(*)
            from test t
           where (t.id > r.begin_
             and t.id <= r.end_) --不是从0开始的计数
             or (t.id >= r.begin_
             and t.id <= r.end_ and r.begin_=0)--从0开始的计数
             ) as count
    from range_ r;