Fix the error “Invalid mix of collations”

If you run a WordPress website, you may encounter the "Invalid Collation Mix" error. This error occurs when the collations in the WordPress database and tables don't match. This can cause issues displaying content on your website. In this article, I'll show you how to fix this error.

What is a collation?

Before we dive into fixing the "Invalid Mix of Collations" error, it's important to understand what a collation is. A collation is a set of rules that determine how characters are sorted and compared in a database. There are several types of collations, including UTF-8, Latin1, and ASCII.

Step-by-step guide to fix the “Invalid Mix of Collations” error

1. Check the WordPress database collation: Open phpMyAdmin or another database management tool and check the WordPress database collation. The collation should match the table collation. If it doesn't, you'll need to change the database collation.

2. Change the WordPress database collation: To change the WordPress database collation, you need to execute a SQL query. Open phpMyAdmin or another database management tool and execute the following query:

ALTER DATABASE database_name CHARACTER SET utf8 COLLATE utf8_general_ci;

Replace "database_name" with the name of your WordPress database. This query changes the database collation to UTF-8.

3. Change the collation of the WordPress tables: Open phpMyAdmin or another database management tool and change the collation of the WordPress tables to UTF-8. Run the following SQL query for each table:

ALTER TABLE table_name CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;

Replace "table_name" with the name of the table. This query changes the table's collation to UTF-8.

4. Check the wp-config.php file: Open the wp-config.php file of your WordPress installation and check for the line “define('DB_CHARSET', 'utf8');” If this line is missing, add it.

5. Check the wp-config.php file again: Check the wp-config.php file again and verify that the line “define('DB_COLLATE', 'utf8_general_ci');” is present. If this line is missing, add it.

6. Check the website: Open your WordPress website and check if the “Invalid mix of collations” error has been resolved.

Conclusion

The "Invalid Collation Mix" error can occur on your WordPress website if the database and table collations do not match. You can resolve this error by changing the database and table collations to UTF-8 and adding lines to the wp-config.php file. It's important to regularly create backups of your WordPress website before making any changes to the database.