yyyyMMddHHmmss转时间格式

loadtime=20181112111111

to_char(to_date(loadtime, 'yyyy-mm-dd hh24:mi:ss'), 'yyyy-mm-dd hh24:mi:ss') 

2018-11-12 11:11:11

 

number转date

to_date(to_char(y.time,'99999999999999'), 'yyyy-mm-dd hh24:mi:ss')

varchar2转换成number

to_number (to_char('20170728000000', '99999999999999'))