SQL mode is a set of configuration options that determine the behavior and syntax of SQL statements executed on a MySQL or MariaDB database. The SQL mode can affect how the database handles data validation, syntax checking, and other aspects of SQL processing.
The SQL mode can be set at the server level, the session level, or the query level. By default, MySQL and MariaDB use a permissive SQL mode that allows for a wide range of SQL syntax and behavior. However, more strict SQL modes are available that enforce stricter standards for data validation, syntax checking, and other aspects of SQL processing.
Some examples of SQL modes that can be set include:
STRICT_TRANS_TABLES: Enforces strict data validation for transactions involving transactional storage engines.
ONLY_FULL_GROUP_BY: Requires all columns in the SELECT list that are not wrapped in an aggregate function to be included in the GROUP BY clause.
NO_ZERO_DATE: Disallows the use of '0000-00-00' as a valid date.
ANSI_QUOTES: Treats double quotes as string delimiters, similar to single quotes.
SQL mode can be modified through configuration files or with SQL statements such as "SET sql_mode='mode_value';". It's important to be aware of the potential impacts of modifying the SQL mode, as changing the SQL mode can affect the behavior of your SQL statements and may require modifications to your code and queries.
The ONLY_FULL_GROUP_BY SQL mode is disabled by default in cPanel shared hosting because it can cause compatibility issues with some applications and scripts that rely on non-standard SQL syntax.
The strict SQL mode enforced by ONLY_FULL_GROUP_BY requires all columns in the SELECT list that are not wrapped in an aggregate function (such as SUM, COUNT, AVG, etc.) to be included in the GROUP BY clause. This can cause issues with applications and scripts that assume that the default behavior of MySQL is to allow columns in the SELECT list that are not included in the GROUP BY clause.
By disabling ONLY_FULL_GROUP_BY mode by default, cPanel allows developers to use MySQL in a more permissive mode that is compatible with a wider range of applications and scripts. However, it's important to note that this can make your database more vulnerable to errors and security issues, and enabling the strict SQL mode is generally recommended for maximum data integrity and security.
The default SQL mode in cPanel MySQL/MariaDB is "NO_ENGINE_SUBSTITUTION". This mode allows for the use of storage engines other than the default engine (which is usually InnoDB), but it does not substitute a different engine if the requested engine is not available.
In addition to "NO_ENGINE_SUBSTITUTION", the default SQL mode in cPanel also includes several other modes that enable a wide range of SQL syntax and behavior. These modes include:
"STRICT_TRANS_TABLES": Enforces strict data validation for transactions involving transactional storage engines.
"NO_ZERO_IN_DATE": Disallows the use of zero values in date and datetime columns.
"NO_ZERO_DATE": Disallows the use of '0000-00-00' as a valid date.
"ERROR_FOR_DIVISION_BY_ZERO": Generates an error when division by zero occurs.
"TRADITIONAL": Combines several other modes, including "STRICT_TRANS_TABLES" and "ERROR_FOR_DIVISION_BY_ZERO", to enforce strict SQL syntax and data validation.
It's worth noting that the default SQL mode in cPanel may vary depending on the version of MySQL or MariaDB that is installed, as well as any custom configuration options
If you want to enable ONLY_FULL_GROUP_BY mode and you have your own VPS hosting, you can do it by changing your MySQL/MariaDB configuration.
Enabling the ONLY_FULL_GROUP_BY SQL mode can help to ensure the data integrity of your database by enforcing strict standards for SQL syntax and data validation. This can help to prevent data loss, corruption, and security vulnerabilities.
However, it's important to be aware that enabling ONLY_FULL_GROUP_BY mode can cause compatibility issues with some applications and scripts that rely on non-standard SQL syntax. If you enable ONLY_FULL_GROUP_BY mode, you may need to modify your code or queries to work with the strict SQL mode.
If you are a server administrator, it's important to carefully consider the potential benefits and drawbacks of enabling ONLY_FULL_GROUP_BY mode for your specific environment and applications. You may want to test your code and SQL queries thoroughly to ensure that they are compatible with the strict SQL mode before making any changes to your server configuration.
Ultimately, the decision to enable ONLY_FULL_GROUP_BY mode will depend on your specific needs and requirements for your database and applications.
and Also possible to enable multiple SQL modes at the same time in cPanel shared hosting. You can do this by specifying a comma-separated list of SQL modes in the "sql_mode" configuration option.
For example, if you want to enable both the STRICT_TRANS_TABLES and ONLY_FULL_GROUP_BY modes, you could add the following line to your MySQL/MariaDB configuration file or run it as an SQL query:
sql_mode = "STRICT_TRANS_TABLES,ONLY_FULL_GROUP_BY"
This would enable both modes simultaneously. You can add or remove SQL modes from this list as needed to customize the behavior of your database.
Keep in mind that enabling multiple SQL modes may impact the compatibility and behavior of your SQL queries, so it's important to thoroughly test your code to ensure that it works correctly with the selected SQL modes
Enabling the ONLY_FULL_GROUP_BY SQL mode in cPanel MySQL has both pros and cons.
Data Integrity: ONLY_FULL_GROUP_BY enforces stricter standards for data validation and syntax checking, which can help to ensure the data integrity of your database.
Prevents unexpected query results: ONLY_FULL_GROUP_BY ensures that all columns in the SELECT list that are not wrapped in an aggregate function (such as SUM, COUNT, AVG, etc.) are included in the GROUP BY clause. This can prevent unexpected query results that can occur when non-aggregated columns are not included in the GROUP BY clause.
Better Query optimization: With ONLY_FULL_GROUP_BY enabled, the MySQL optimizer can use more advanced query optimization techniques, which can lead to better performance in some cases.
Compatibility issues: ONLY_FULL_GROUP_BY can cause compatibility issues with some applications and scripts that rely on non-standard SQL syntax. Enabling this mode may require modifications to your code and queries to ensure compatibility.
Increased development effort: Modifying your code and queries to work with ONLY_FULL_GROUP_BY can require additional development effort, which may increase your development time and cost.
Not suitable for some use cases: ONLY_FULL_GROUP_BY may not be suitable for some use cases where you need to optimize for performance over data integrity.
In summary, enabling ONLY_FULL_GROUP_BY in cPanel MySQL can help to ensure data integrity and prevent unexpected query results. However, it may require modifications to your code and queries and can cause compatibility issues with some applications and scripts. As with any configuration change, it's important to thoroughly test your code and queries after enabling ONLY_FULL_GROUP_BY to ensure that everything works as expected.