oracle between and 边界问题

--创立一个表
create table test_hsj(
id int primary key,
num varchar2(12),
regDate date
)


select * from test_hsj;

--插入测试数据
insert into test_hsj values(1,"1", to_date("2015-05-01","yyyy-MM-dd"))
insert into test_hsj values(2,"2", to_date("2015-06-01","yyyy-MM-dd"))
insert into test_hsj values(3,"3", to_date("2015-05-11","yyyy-MM-dd"))
insert into test_hsj values(4,"4", to_date("2015-05-01","yyyy-MM-dd"))
insert into test_hsj values(5,"5", to_date("2015-06-21","yyyy-MM-dd"))
insert into test_hsj values(6,"6", to_date("2015-06-11","yyyy-MM-dd"))
insert into test_hsj values(7,"7", to_date("2016-06-11","yyyy-MM-dd"))
insert into test_hsj values(8,"8", to_date("2014-04-01","yyyy-MM-dd"))
--查询验证，日期在 5 月到6月份之间的数据 如果转换为日期的时候，只有年月的时候会默许取1号 between and 会包括两端 包括两端
--1 结论：对日期类型 between and  包括  >= and <=
select * from test_hsj where regdate between to_date("2015-05","yyyy-MM") and to_date("2015-06","yyyy-MM")
--如果只有年月 则只会去 1号
select to_date("2015-05","yyyy-MM") from dual
--如果只有年，那末回去当前月份 的1 号 
select to_date("2014","yyyy") from dual
--2 结论： 对数值类型 between and  等效  >= and <=
select * from test_hsj where id between 1 and 5;

--3 结论： 对字符类型 between and  等效  >= and <=
select * from test_hsj where num between "1" and "5";
--总结论： 对orcle数据库 between and  等效  >= and <=
--创立一个表
create table test_hsj(
id int primary key,