Why Does \"Harligt\" and \"Härligt\" Return the Same Results in MySQL? A Look at Collation and Character Normalization.

MySQL's Treatment of Special Characters: A Paradox Explained

In MySQL, executing queries involving special characters like 'Å', 'Ä', and 'Ö' often raises questions regarding result consistency. For instance, queries with 'Harligt' and 'Härligt' yield identical results, leaving users perplexed.

This phenomenon is attributed to MySQL's default collation settings, specifically "utf8_general_ci" and "utf8_unicode_ci." These collations normalize certain unicode characters, including Scandinavian letters, by equating them to their English equivalents (e.g., "Ä = A"). This normalization simplifies comparison operations and searches but can be inconvenient in certain scenarios.

To resolve this issue, consider the following options:

• Use a Different Collation: Collations like "utf8_bin" preserve character values, including special characters, but may have implications for other operations.
• Specify Collation in Queries: For specific queries where you want to override the default collation, append "COLLATE utf8_bin" to the query. Example:

select * from topics where name='Harligt' COLLATE utf8_bin;

• Create a Custom Collation: If neither of the above solutions meet your needs, you can create a custom collation that suits your specific requirements.

It's worth noting that case-insensitive LIKE operations in MySQL cannot be performed without the normalization of special characters. However, related discussions can be found here:

• [Looking for case insensitive MySQL collation where “a” != “ä”](https://dba.stackexchange.com/questions/231116/looking-for-case-insensitive-mysql-collation-where-a-a)
• [MYSQL case sensitive search for utf8_bin field](https://stackoverflow.com/questions/9704962/mysql-case-sensitive-search-for-utf8-bin-field)

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