oraclebetweenand边界问题

oraclebetweenand边界问题

--创建一个表
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认取1号 between and 会包含两端 包含两端
--1 结论：对于日期类型 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，那么回去当前月份 的1 号 
select to_date('2014','yyyy') from dual
--2 结论： 对于数值类型 between and  等效  >= and <=
select * from test_hsj where id between 1 and 5;

--3 结论： 对于字符类型 between and  等效  >= and <=
select * from test_hsj where num between '1' and '5';
--总结论： 对于orcle数据库 between and  等效  >= and <=