oracle-timestamp类型处理

DATE类型转换为TIMESTAMP

SELECT CAST(sysdate AS TIMESTAMP) from dual;

VARCHAR类型转换为TIMESTAMP

SELECT CAST(to_date(‘20110419010101’,’yyyy-mm-dd hh24:mi:ss’) AS TIMESTAMP) from dual;

TIMESTAMP类型转换为VARCHAR

select to_char(systimestamp,'yyyy-mm-dd hh24:mi:ss.ff3') from dual;--------3位精度
select to_char(systimestamp,'yyyy-mm-dd hh24:mi:ss.ff') from dual;--------6位精度
select to_char(systimestamp,'ff6') from dual