oracle 格式化日期

Formatting DATE in oracle(oracle 格式化日期)
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问题描述

我在包含 dd-MMM-yy 格式的日期的表中有一个日期字段.

I have a date field in a table that contains date in dd-MMM-yy format .

我想创建一个函数,让这个日期检查它是否为空,然后将其更改为 yyyy/mm/dd 格式

I want to create a function that get this date check it for not null and then change it to yyyy/mm/dd format

但问题是 oracle 不接受 dd-MMM-yy 格式日期作为输入参数和它说:请使用 yyyy-MM-dd 日期格式!!!

but the problem is that oracle doesn't accept dd-MMM-yy formate date as a input parameter and it say : Please Use yyyy-MM-dd date format !!!

我如何首先将 dd-MMM-yy 格式更改为 yyyy-MM-dd,以便 oracle 接受它作为输入然后将其更改为 yyyy/mm/dd

how can I first change dd-MMM-yy formate to yyyy-MM-dd so oracle accept it as input then change it to yyyy/mm/dd

推荐答案

: 请使用 yyyy-MM-dd 日期格式!!!

: Please Use yyyy-MM-dd date format !!!

这与 Oracle 错误无关.

That is no way related to an Oracle error.

我在包含 dd-MMM-yy 格式的日期的表中有一个日期字段.

I have a date field in a table that contains date in dd-MMM-yy format .

不,你很困惑.Oracle 不会以您看到的格式存储日期.它在内部以 7 个字节存储它,每个字节存储日期时间值的不同组成部分.

No, you are confused. Oracle does not store dates in the format you see. It stores it internally in 7 bytes with each byte storing different components of the datetime value.

Byte    Description
----    -------------------------------------------------
1       Century value but before storing it add 100 to it
2       Year and 100 is added to it before storing
3       Month
4       Day of the month
5       Hours but add 1 before storing it
6       Minutes but add 1 before storing it
7       Seconds but add 1 before storing it

如果要显示,请使用TO_CHAR和适当的FORMAT MODEL.

If you want to display, use TO_CHAR with proper FORMAT MODEL.

插入时,使用TO_DATE和适当的FORMAT MODEL.

While inserting, use TO_DATE with proper FORMAT MODEL.

默认情况下,您看到的格式是您的特定于区域设置的 NLS 设置.

What you see as a format by default, is your locale specific NLS settings.

SQL> select parameter, value from v$nls_parameters where parameter='NLS_DATE_FORMAT';

PARAMETER       VALUE
--------------- ----------------------------------------------------------------
NLS_DATE_FORMAT DD-MON-RR

SQL> select sysdate from dual;

SYSDATE
---------
03-FEB-15

SQL> select to_char(sysdate, 'mm/dd/yyyy hh24:mi:ss') from dual;

TO_CHAR(SYSDATE,'MM
-------------------
02/03/2015 17:59:42

SQL>

更新关于MMM格式.

对于 MMM,如果您指的是最多三个字符的月份名称,请使用 MON.

By MMM if you mean the month name up to three characters, then use MON.

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