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  1. MariaDB Server
  2. MDEV-8319

ERROR_FOR_DIVISION_BY_ZERO not throwing error

Details

    • Bug
    • Status: Closed (View Workflow)
    • Major
    • Resolution: Fixed
    • 10.0.19
    • N/A
    • Documentation
    • None
    • Windows 8.1

    Description

      ERROR_FOR_DIVISION_BY_ZERO doesn't appear to be honored.

      Welcome to the MariaDB monitor.  Commands end with ; or \g.
      		 
      Your MariaDB connection id is 1043
      		 
      Server version: 10.0.19-MariaDB mariadb.org binary distribution
      		 
       
      		 
      Copyright (c) 2000, 2015, Oracle, MariaDB Corporation Ab and others.
      		 
       
      		 
      Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
      		 
       
      		 
      MariaDB [(none)]> SHOW VARIABLES LIKE 'sql_mode';
      		 
      +---------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
      		 
      | Variable_name | Value                          |
      		 
      +---------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
      		 
      | sql_mode      | ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,STRICT_ALL_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,TRADITIONAL,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION |
      		 
      +---------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
      		 
      1 row in set (0.00 sec)
      		 
       
      		 
      MariaDB [(none)]> SELECT 1/0;
      		 
      +------+
      		 
      | 1/0  |
      		 
      +------+
      		 
      | NULL |
      		 
      +------+
      		 
      1 row in set, 1 warning (0.00 sec)
      		 
       
      		 
      MariaDB [(none)]> show warnings;
      		 
      +---------+------+---------------+
      		 
      | Level   | Code | Message       |
      		 
      +---------+------+---------------+
      		 
      | Warning | 1365 | Division by 0 |
      		 
      +---------+------+---------------+
      		 
      1 row in set (0.00 sec)

      There is a warning, but according to https://mariadb.com/kb/en/mariadb/sql_mode/ it should "Return a 1365 'Division by 0' error (instead of a warning)"

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          greenman Ian Gilfillan added a comment -

          I am not sure what the intended behaviour is - to me it looks like a bug, as you would expect an option called "ERROR_*" to actually return an error, at least in strict mode. I have tested the behaviour on MariaDB 5.5, MySQL 5.6.19 and it works in the same undocumented way as well. The option has also been deprecated in MySQL 5.6. I'll update the documentation to reflect what happens now, but leaving the task open for re-assigning if its seen as a bug rather than intentional.

          greenman Ian Gilfillan added a comment - I am not sure what the intended behaviour is - to me it looks like a bug, as you would expect an option called "ERROR_*" to actually return an error, at least in strict mode. I have tested the behaviour on MariaDB 5.5, MySQL 5.6.19 and it works in the same undocumented way as well. The option has also been deprecated in MySQL 5.6. I'll update the documentation to reflect what happens now, but leaving the task open for re-assigning if its seen as a bug rather than intentional.
          Sparticuz Kyle McNally added a comment -

          According to this: https://dev.mysql.com/doc/refman/5.6/en/sql-mode.html#sqlmode_error_for_division_by_zero

          It looks like the warning would almost suffice: "If this mode is enabled, division by zero inserts NULL and produces a warning."
          Which is the behavior we see.

          However, "If this mode and strict mode are enabled, division by zero produces an error,..." which was the previously documented outcome.

          Either is fine with me. It doesn't affect my program at all. I was just tightening up my server after switching from MySql and noticed that this mode wasn't the same as the documentation.

          Sparticuz Kyle McNally added a comment - According to this: https://dev.mysql.com/doc/refman/5.6/en/sql-mode.html#sqlmode_error_for_division_by_zero It looks like the warning would almost suffice: "If this mode is enabled, division by zero inserts NULL and produces a warning." Which is the behavior we see. However, "If this mode and strict mode are enabled, division by zero produces an error,..." which was the previously documented outcome. Either is fine with me. It doesn't affect my program at all. I was just tightening up my server after switching from MySql and noticed that this mode wasn't the same as the documentation.

          People

            greenman Ian Gilfillan
            Sparticuz Kyle McNally
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            Dates

              Created:
              Updated:
              Resolved:

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