MySQL 5.7 STR_TO_DATE [英] MySQL 5.7 STR_TO_DATE

问题描述

我正在运行 MySQL 5.7 并希望将一些字符串转换为日期.我在这里参考了手册:http://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_str-to-date

I am running MySQL 5.7 and wanted to convert some strings to date. I referred the manual here: http://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_str-to-date

并尝试了以下(请注意MySQL版本)

And tried out the following(please note the MySQL version)

mysql> SELECT STR_TO_DATE('9','%m');
+-----------------------+
| STR_TO_DATE('9','%m') |
+-----------------------+
| NULL                  |
+-----------------------+
1 row in set, 1 warning (0.00 sec)

mysql> show warnings;
+---------+------+--------------------------------------------------------+
| Level   | Code | Message                                                |
+---------+------+--------------------------------------------------------+
| Warning | 1411 | Incorrect datetime value: '9' for function str_to_date |
+---------+------+--------------------------------------------------------+
1 row in set (0.00 sec)

但是从 MySQL 5.7 的在线手册中，我应该看到以下内容:

But from the online manual for MySQL 5.7, I should see the following:

mysql> SELECT STR_TO_DATE('9','%m');
        -> '0000-09-00'

是否有什么我遗漏的地方，或者这可能是一个错误?

Is there something that I'm missing, or could this be a bug?

推荐答案

正如手册中所说，

如果启用了 NO_ZERO_DATE 或 NO_ZERO_IN_DATE SQL 模式，则不允许使用零日期或部分日期.在这种情况下，STR_TO_DATE() 返回 NULL 并生成警告

If the NO_ZERO_DATE or NO_ZERO_IN_DATE SQL mode is enabled, zero dates or part of dates are disallowed. In that case, STR_TO_DATE() returns NULL and generates a warning

在这种情况下，这会导致结果为 NULL，因为您的部分日期"包含零值.

That causes the result to be NULL in cases such like this, because your partial "date" contains zero values.

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