sql中时间的比较

经常在写sql语句的时候会有关事件的比较的，现在总结一下：
mysql中字段类型为datetime的比较为：
select * from service_domain sd where apply_date between '2011-01-01' and '2011-06-23' order by sd.apply_date desc

oracle中字段类型为date类型的，sql如下：
1.select * from service_domain sd  where  to_char(sd.apply_date, 'yyyy-MM-dd') >= '2011-01-21'
and to_char(sd.apply_date, 'yyyy-MM-dd') <= '2011-06-23'

2.select * from service_domain sd  where  sd.apply_date > = TO_DATE('2011-01-01 00:00:00','YYYY-MM-DD HH24:MI:SS')
and sd.apply_date <= TO_DATE('2011-06-23 23:59:59','YYYY-MM-DD HH24:MI:SS')