META 值 charset=UTF-8 防止 UTF-8 字符显示
我制作了一个测试程序，它基本上只是一个可以输入字符的文本区域，当我单击“提交”时，字符将被写入 MySQL 测试表（使用 PHP）。
测试表的排序规则是UTF-8。
如果我想将 é 或 ú 写入它可以正常写入的数据库，该脚本可以正常工作。但是，如果我将以下元语句添加到页面的 区域：
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
...字符开始变得混乱。
我的理论是，服务器强加了一些运行良好的编码，但是当我添加 UTF-8 指令时，它会覆盖此服务器编码，并且此 UTF-* 编码不包含诸如 é 和 ú。 但我认为 UTF-8 编码了所有（克林贡语等）字符。
基本上我的程序可以工作，但我想知道为什么当我添加指令时它不起作用。 我想我错过了一些东西。
非常感谢任何帮助/教导。
提前致谢。
I've made a test program that is basically just a textarea that I can enter characters into and when I click submit the characters are written to a MySQL test table (using PHP).
The test table is collation is UTF-8.
The script works fine if I want to write a é or ú to the database it writes fine. But then if I add the following meta statement to the <head> area of my page:
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
...the characters start becoming scrambled.
My theory is that the server is imposing some encoding that works well, but when I add the UTF-8 directive it overrides this server encoding and that this UTF-* encoding doesn't include the characters such as é and ú.
But I thought that UTF-8 encoded all (bar Klingon etc) characters.
Basically my program works but I want to know why when I add the directive it doesn't.
I think I'm missing something.
Any help/teaching most appreciated.
Thanks in advance.
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首先，PHP 通常不处理 Unicode 字符集或 UTF-8 字符编码。除了（小心使用）mb_... 函数之外，它仅将字符串视为二进制数据。
其次，您需要告诉 MySQL 客户端库您正在使用什么字符集/编码。 “SET NAMES”SQL 命令完成这项工作，不同的 MySQL 客户端（mysql、mysqli 等）以不同的方式提供对其的访问，例如 http://www.php.net/manual/en/mysqli.set-charset.php
您的浏览器和 MySQL 客户端可能是两者都默认为 latin1，并且巧合地匹配。 MySQL 然后知道将 latin1 二进制数据转换为 UTF-8。当您将浏览器字符集/编码设置为 UTF-8 时，MySQL 客户端会将 UTF-8 数据解释为 latin1，并错误地对其进行转码。
因此，解决方案是将 MySQL 客户端设置为与浏览器对 PHP 的输入相匹配的字符集。
另请注意，表排序规则与表字符集不同 - 排序规则是指字符串的比较和排序方式。令人困惑的事情，希望这有帮助！
Firstly, PHP generally doesn't handle the Unicode character set or UTF-8 character encoding. With the exception of (careful use of) mb_... functions, it just treats strings as binary data.
Secondly, you need to tell the MySQL client library what character set / encoding you're working with. The 'SET NAMES' SQL command does the job, and different MySQL clients (mysql, mysqli etc..) provide access to it in different ways, e.g. http://www.php.net/manual/en/mysqli.set-charset.php
Your browser, and MySQL client, are probably both defaulting to latin1, and coincidentally matching. MySQL then knows to convert the latin1 binary data into UTF-8. When you set the browser charset/encoding to UTF-8, the MySQL client is interpreting that UTF-8 data as latin1, and incorrectly transcoding it.
So the solution is to set the MySQL client to a charset matching the input to PHP from the browser.
Note also that table collation isn't the same as table character set - collation refers to how strings are compared and sorted. Confusing stuff, hope this helps!