oracle函数总结

--取系统时间
1.select sysdate from dual;
2.select to_char(sysdate,'yyyy/mm/dd hh:mi:ss') from dual;
--取年，月，日
1.select extract(year from sysdate) from dual;
2.select extract(month from sysdate) from dual;
3.select extract(day from sysdate) from dual;