把格林威治时间转换为北京时间的函数

create or replace function Fun_SecondToTime(iamt number) return  varchar
as
mytime varchar(24);
begin
 select to_char(to_date(19700101,'yyyymmdd')+(iamt/60/60/24)+(8/24),'yyyy-mm-dd hh24:mi:ss')
       into mytime
 from dual;
 return mytime;

end Fun_SecondToTime;