to_char与to_date的区别

select * from csend where credttm > to_date('2018-06-11','yyyy-mm-dd');

select * from csend where to_char(credttm,'yyyy-mm-dd')>'2018-06-25'

结论：to char 是把日期或数字转换为字符串
to date 是把字符串转换为数据库中得日期类型