Bug #79925 String const '69E5' is not treated as scientific notation when casting to int

• Submitted: 12 Jan 2016 8:07
• Modified: 12 Jan 2016 9:35
• Reporter: Su Dylan
• Status: Verified
• Category: MySQL Server: DML
• Severity: S3 (Non-critical)
• Version: 5.7.8, 5.5.48, 5.6.28, 5.7.10
• OS: Any
• CPU Architecture: Any

[12 Jan 2016 8:07] Su Dylan

Description:
Output:
=====
mysql> select cast('69E5' as decimal ), cast('69E5' as signed);
+--------------------------+------------------------+
| cast('69E5' as decimal ) | cast('69E5' as signed) |
+--------------------------+------------------------+
|                  6900000 |                     69 |
+--------------------------+------------------------+
1 row in set, 1 warning (0.00 sec)

mysql> select version();
+-----------+
| version() |
+-----------+
| 5.7.8-rc  |
+-----------+
1 row in set (0.00 sec)

Problem:
=====
"cast('69E5' as signed) " is expected to return 6900000

How to repeat:
select cast('69E5' as decimal ), cast('69E5' as signed);

Suggested fix:
690000 is returned for 'cast('69E5' as signed) '.

[12 Jan 2016 9:35] MySQL Verification Team

Hello Su Dylan,

Thank you for the report and test case.
Observed that 5.5.48/5.6.28/5.7.10 are affected.

Thanks,
Umesh

[10 Apr 2023 2:40] dick Dick

As far as I know, string->int it's going to look for the first number until it hits a non-number and then cast those numbers as the result.
Change signed to double or float results in 6900,000.
So these are two different conversion strategies