About date type query in database

     Generally speaking, date queries do not involve time queries, but some time fields in the database table will contain time content, which will lead to inaccurate query results. There are generally two solutions:

  1. Add the time when querying, the start time is "00:00:00", the end time is "23:59:59", the relevant code

date_time>= to_date('2016-04-04 00:00:00', 'yyyy-MM-dd hh24:mi:ss')
date_time <= to_date('2016-07-22 23:59:59', 'yyyy-MM-dd hh24:mi:ss')

    2. Convert time type to character type, related code

to_char(date_time,'yyyy-mm-dd') >= '2016-04-04'
to_char(date_time,'yyyy-mm-dd') <= '2016-07-22'

           A way of writing characters without '-'

to_char(date_time,'yyyymmdd') >= to_char(to_date('2016-04-04','yyyy-mm-dd'),'yyyymmdd')
to_char(date_time,'yyyymmdd') <= to_char(to_date('2016-07-22','yyyy-mm-dd'),'yyyymmdd')