Using mysqli::set_charset Always Results in Garbled Text? Here’s How to Troubleshoot the Root Cause

gitbox 2025-08-17

<span><span><span><?php</span></span><span>
</span><span><span>// Example code unrelated to the main content at the beginning of this article</span></span><span>
</span><span><span>echo</span></span><span> </span><span><span>"Welcome to reading technical articles!"</span></span><span>;
</span><span><span>?></span></span><span>
<p><hr></p>
<p></span><?php<br>
// Main content starts</p>
<p>echo "<h1>Using mysqli::set_charset Always Results in Garbled Text? Here’s How to Troubleshoot the Root Cause</h1>";</p>
<p>echo "<p>If the database or table charset is not utf8mb4, it is recommended to run ALTER DATABASE and ALTER TABLE to make changes.</p>";</p>
<p>echo "<h2>2. Use mysqli::set_charset to Set Connection Charset</h2>";<br>
echo "<p>Correct usage example:</p>"<br>
echo "<pre>$mysqli = new mysqli('localhost', 'user', 'password', 'dbname');\nif (!$mysqli->set_charset('utf8mb4')) {\n    printf('Error: Unable to set charset %s\n', $mysqli->error);\n    exit();\n}

";
echo "
Make sure set_charset is called before any queries are executed, and that the charset name is correct (it is recommended to use utf8mb4 instead of utf8, since MySQL’s utf8 does not support all Unicode characters).
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echo "
3. Ensure Page Encoding Matches Output Encoding
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echo "The HTML header of the page should declare the correct charset, for example:
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echo "<meta charset='UTF-8'>
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echo "Also ensure that the PHP code file itself is saved in UTF-8 without BOM to avoid garbled output.
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echo "
4. Check How Data Is Stored and Retrieved
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echo "If data was inserted using the wrong charset, the data itself is already corrupted. Use client tools (such as MySQL Workbench) to verify whether the data is stored correctly. If the data is correct but still displays as garbled text, the issue may be with the PHP connection charset or page encoding settings.
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echo "
5. Common Mistakes to Avoid
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echo "";

echo "Do not mix SET NAMES and set_charset. They serve similar purposes but it is recommended to use only set_charset.
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echo "Avoid switching charsets multiple times on the same connection, which can cause confusion.
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echo "Check that the database server configuration option character_set_server is compatible with the application’s charset.
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echo "
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echo "
Conclusion
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echo "Charset issues may seem complicated, but by systematically checking the database charset, connection charset, page encoding, and the data itself, you can pinpoint the root cause. It is recommended to use utf8mb4 consistently and rely on mysqli::set_charset to set the connection charset, avoiding garbled text problems.
";

?>

Related Tags:
mysqli

mysqli::set_charset