Make a backup! Then you need to set the default char sets on the database. This does not convert existing tables, it only sets the default for newly created tables. ALTER DATABASE dbname CHARACTER SET utf8 COLLATE utf8_general_ci; Then, you will need to convert the char set on all existing tables and their columns. This assumes that your current data is actually in the current char set. If your columns are set to one char set but your data is really stored in another then you will need to check the MySQL manual on how to handle this. ALTER TABLE tbl_name CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;

你也可以使用数据库工具Navicat，这样做更容易。

湿 婆。

右键单击您的数据库，并在下拉菜单中选择数据库属性和更改

如果数据不在相同的字符集中，您可以考虑http://dev.mysql.com/doc/refman/5.0/en/charset-conversion.html中的这个片段

如果列具有非二进制数据类型(CHAR、VARCHAR、TEXT)，则其 内容应该在列字符集中编码，而不是其他字符集 字符集。如果内容用不同的字符编码 设置后，您可以先将列转换为使用二进制数据类型，然后 然后转换到具有所需字符集的非二进制列。

这里有一个例子:

 ALTER TABLE t1 CHANGE c1 c1 BLOB;
 ALTER TABLE t1 CHANGE c1 c1 VARCHAR(100) CHARACTER SET utf8;

确保选择正确的排序规则，否则可能会得到唯一的键冲突。如。 Éleanore和Eleanore在某些排序中可能被认为是相同的。

旁白:

我曾遇到过这样的情况，电子邮件中的某些字符“坏了”，尽管它们在数据库中以UTF-8格式存储。如果您使用utf8数据发送电子邮件，您可能还需要将电子邮件转换为utf8发送。

在phpailer中，只需更新这一行:public $CharSet = 'utf-8';

要将字符集编码更改为UTF-8，请在PHPMyAdmin中执行简单步骤

选择数据库 进入操作区 在操作选项卡中，在底部排序规则下拉菜单中，选择您想要的编码，即(utf8_general_ci)，并勾选复选框(1)更改所有表排序规则，(2)更改所有表列排序规则。然后点击Go。

使用HeidiSQL。它是免费的，而且是一个非常好的数据库工具。

从工具菜单，进入批量表编辑器

选择完整的数据库或选择表进行转换，

tick更改默认排序规则:utf8mb4_general_ci tick转换为字符集:utf8

执行

这将在短短几秒钟内将完整的数据库从拉丁语转换为utf8。

工作就像一个魅力:)

HeidiSQL默认连接为utf8，因此任何特殊字符现在都应该被视为字符(æ ø å)，而不是在检查表数据时被编码。

从latin到utf8的真正陷阱是确保pdo与utf8字符集连接。如果不是，你会得到垃圾数据插入到utf8表和问号在你的网页上到处都是，让你认为表数据不是utf8…

在继续之前，请确保您:已完成完全数据库备份!

步骤1:数据库级别更改

标识数据库的排序规则和字符集 选择default_character_set_name, default_collation_name from information_schema。图式年代 WHERE schema_name = 'your_database_name' 和 (DEFAULT_CHARACTER_SET_NAME != 'utf8' 或 DEFAULT_COLLATION_NAME不像'utf8%'); 修复数据库的排序规则 ALTER DATABASE DATABASE utf8 COLLATE utf8_unicode_ci;

步骤2:表级别更改

Identifying Database Tables with the incorrect character set or collation SELECT CONCAT( 'ALTER TABLE ', table_name, ' CHARACTER SET utf8 COLLATE utf8_general_ci; ', 'ALTER TABLE ', table_name, ' CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci; ') FROM information_schema.TABLES AS T, information_schema.`COLLATION_CHARACTER_SET_APPLICABILITY` AS C WHERE C.collation_name = T.table_collation AND T.table_schema = 'your_database_name' AND (C.CHARACTER_SET_NAME != 'utf8' OR C.COLLATION_NAME not like 'utf8%') Adjusting table columns' collation and character set

捕获上层sql输出并运行它。(如后)

ALTER TABLE rma CHARACTER SET utf8 COLLATE utf8_general_ci;ALTER TABLE rma CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;  
ALTER TABLE rma_history CHARACTER SET utf8 COLLATE utf8_general_ci;ALTER TABLE rma_history CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;  
ALTER TABLE rma_products CHARACTER SET utf8 COLLATE utf8_general_ci;ALTER TABLE rma_products CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;  
ALTER TABLE rma_report_period CHARACTER SET utf8 COLLATE utf8_general_ci;ALTER TABLE rma_report_period CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;  
ALTER TABLE rma_reservation CHARACTER SET utf8 COLLATE utf8_general_ci;ALTER TABLE rma_reservation CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;  
ALTER TABLE rma_supplier_return CHARACTER SET utf8 COLLATE utf8_general_ci;ALTER TABLE rma_supplier_return CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;  
ALTER TABLE rma_supplier_return_history CHARACTER SET utf8 COLLATE utf8_general_ci;ALTER TABLE rma_supplier_return_history CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;  
ALTER TABLE rma_supplier_return_product CHARACTER SET utf8 COLLATE utf8_general_ci;ALTER TABLE rma_supplier_return_product CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci; 

参考网址:https://confluence.atlassian.com/display/CONFKB/How+to+Fix+the+Collation+and+Character+Set+of+a+MySQL+Database