Bug #85035 str_to_date with mismatched parameters should have failed

• Submitted: 17 Feb 2017 4:12
• Modified: 17 Feb 2017 10:17
• Reporter: 帅 Bang
• Status: Verified
• Category: MySQL Server: DML
• Severity: S3 (Non-critical)
• Version: 5.6, 5.6.35, 5.7.17
• OS: Linux
• CPU Architecture: Any

[17 Feb 2017 4:12] 帅 Bang

Description:
MySQL:
mysql>  select str_to_date("1997-10-04","%Y-%m-%D");
+--------------------------------------+
| str_to_date("1997-10-04","%Y-%m-%D") |
+--------------------------------------+
| 1997-10-04                           |
+--------------------------------------+
1 row in set (0.00 sec)

seems quite nice and considerate for users. However, it contradicts with the doc described here:

https://dev.mysql.com/doc/refman/5.6/en/date-and-time-functions.html#function_date-format

%D	Day of the month with English suffix (0th, 1st, 2nd, 3rd, …)

So, it should have failed. 

How to repeat:
select str_to_date("1997-10-04","%Y-%m-%D");

Suggested fix:
returns NULL with a warning

[17 Feb 2017 10:17] MySQL Verification Team

Hello Bang,

Thank you for the report and test case.

Thanks,
Umesh