ORACLE中date和timestamp的相互轉化

date轉爲timstamp
date轉爲timstam能夠函數to_timestamp的方式來轉化：

SELECT to_timestamp('2018-06-19 12:10:10.1','yyyy-mm-dd hh24:mi:ss.ff')
FROM dual;

timestamp轉化爲date
1, timestamp+0
select Systimestamp+0 FROM DUAL;

2, to_char的方式
Select to_char(Systimestamp,'yyyymmdd') From dual;

3，cast轉化
 Select Cast(Systimestamp As Date) From dual;