对于24小时的时间，你需要使用 HH24 而不是 HH 。

For the 24-hour time, you need to use HH24 instead of HH.

对于12小时的时间， AM / PM指标写为 AM （如果您想要结果中的期间）或 AM （如果你't）。例如：

For the 12-hour time, the AM/PM indicator is written as A.M. (if you want periods in the result) or AM (if you don't). For example:

SELECT invoice_date,
       TO_CHAR(invoice_date, 'DD-MM-YYYY HH24:MI:SS') "Date 24Hr",
       TO_CHAR(invoice_date, 'DD-MM-YYYY HH:MI:SS AM') "Date 12Hr"
  FROM invoices
;

有关格式模型的更多信息，可以使用 TO_CHAR ，请参阅 http://docs.oracle.com /cd/E16655_01/server.121/e17750/ch4datetime.htm#NLSPG004 。

For more information on the format models you can use with TO_CHAR on a date, see http://docs.oracle.com/cd/E16655_01/server.121/e17750/ch4datetime.htm#NLSPG004.