oracle中时间问题 - Oracle / 基础和管理

1.日期格式中的“J”和“jsp”表示什么意思？
select to_char(to_date(222,'J'),'jsp') from dual;
select to_char(to_date(222,'J'),'JSP') from dual;  
select to_char(to_date(222,'J'),'Jsp') from dual;  

2.计算08年奥运会(2008-08-08 20:00:00) 距离当前时间已过了多少天多少小时多少分多少秒? 求SQL!

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SQL code:
SQL> --1、这个很有意思，可以将数字转换成英文
SQL> SELECT to_char(to_date(222, 'J'), 'jsp') from dual;

TO_CHAR(TO_DATE(222,'J'),'JSP'
---------------------------------------------------------------------------
two hundred twenty-two

SQL> SELECT to_char(to_date(222, 'J'), 'JSP') from dual;

TO_CHAR(TO_DATE(222,'J'),'JSP'
---------------------------------------------------------------------------
TWO HUNDRED TWENTY-TWO

SQL> SELECT to_char(to_date(222, 'J'), 'Jsp') from dual;

TO_CHAR(TO_DATE(222,'J'),'JSP'
---------------------------------------------------------------------------
Two Hundred Twenty-Two

SQL> --2、时间差
SQL> WITH tt AS
2 (SELECT SYSDATE - to_date('2008-08-08 20:00:00', 'yyyy-mm-dd hh24:mi:ss') dt from dual)
3 SELECT '奥运会距今已过:' || trunc(dt) || '天' || trunc((dt - trunc(dt)) * 24) || '小时' ||
4 trunc((dt * 24 - trunc(dt * 24)) * 60) || '分' || trunc((dt * 1440 - trunc(dt * 1440)) *
60) || '秒' diff
5 from tt;

DIFF
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