您可以在以下级别设置默认排序规则:

http://dev.mysql.com/doc/refman/5.0/en/charset-syntax.html

1)客户端 2)服务器默认 3)数据库默认 4)表默认 5)列

您可以通过PHP脚本更改所有表的CHARSET和COLLATION，如下所示。我喜欢hkasera的答案，但它的问题是查询在每个表上运行两次。这段代码几乎是一样的，除了使用MySqli而不是mysql和防止双重查询。如果我可以投票的话，我会给hkasera的答案投票。

<?php
$conn1=new MySQLi("localhost","user","password","database");
if($conn1->connect_errno){
    echo mysqli_connect_error();
    exit;
}
$res=$conn1->query("show tables") or die($conn1->error);
while($tables=$res->fetch_array()){
    $conn1->query("ALTER TABLE $tables[0] CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci") or die($conn1->error);
}
echo "The collation of your database has been successfully changed!";

$res->free();
$conn1->close();

?>

要更改表的排序规则，您可以使用，

ALTER TABLE mytable CONVERT TO CHARACTER SET utf8

若要为整个数据库设置默认排序规则，请执行以下操作

ALTER DATABASE  `databasename` DEFAULT CHARACTER SET utf8 COLLATE utf8_bin

否则,

Goto PhpMyAdmin - >操作- >排序。

在这里，您可以找到包含所有现有排序规则的选择框。这样你就可以改变排序规则。在创建新列时，数据库表将遵循这个排序规则。创建新列时不需要选择排序规则。

注意,在改变数据库的字符集/表/列,实际上你可能需要将现有的数据(例如,如果你看到类似“U…Ø·U”ˆØ¨ØªUˆØ±UŠØ¯Ø¬U”)是这样的:

update country set name = convert(cast(convert(name using latin1) as binary) using utf8), cn_flag = convert(cast(convert(cn_flag using latin1) as binary) using utf8), and so on..

对于转换数据库、表和字段，我建议从这个线程中得到这个答案，它会生成一组大的查询，你只需要在粘贴时复制，在这里我还找不到一个自动的解决方案。 还要注意的是，如果你将同一个字段转换两次，你将得到不可恢复的问号:"?? "。如果在转换字段/表之前转换数据，也会得到这个问号。

修改数据库中所有表中所有字段的排序规则。

我只是通过前面提到的Php为表中的字段添加另一个循环到解决方案。这很有帮助，表中的所有字段也都转换了。

<?php
$con = mysql_connect('localhost','user','pw');
if(!$con) { echo "Cannot connect to the database ";die();}
mysql_select_db('database_name');
$result=mysql_query('show tables');
while($tables = mysql_fetch_array($result)) {

foreach ($tables as $key => $table) {                   // for each table

    $sql = "ALTER TABLE $table CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci";
    echo "\n".$sql;
    mysql_query($sql);

    $sql = "show fields in ".$table." where type like 'varchar%' or type like 'char%' or type='text' or type='mediumtext';";
    $rs2=mysql_query($sql);
    while( $rw2 = mysql_fetch_array($rs2) ){            // for each field in table

        $sql = "ALTER TABLE `".$table."` CHANGE `".$rw2['Field']."` `".$rw2['Field']."` ".$rw2['Type']." CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL;";
        echo "\n".$sql;
        mysql_query($sql);

    } 


}
}
echo "The collation of your database has been successfully changed!";

?>}

我在这里读到，你需要手动转换每个表，这是不正确的。下面是一个如何使用存储过程的解决方案:

DELIMITER $$

DROP PROCEDURE IF EXISTS changeCollation$$

-- character_set parameter could be 'utf8'
-- or 'latin1' or any other valid character set
CREATE PROCEDURE changeCollation(IN character_set VARCHAR(255))
BEGIN
DECLARE v_finished INTEGER DEFAULT 0;
DECLARE v_table_name varchar(255) DEFAULT "";
DECLARE v_message varchar(4000) DEFAULT "No records";

-- This will create a cursor that selects each table,
-- where the character set is not the one
-- that is defined in the parameter

DECLARE alter_cursor CURSOR FOR SELECT DISTINCT TABLE_NAME
FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA = DATABASE()
AND COLLATION_NAME NOT LIKE CONCAT(character_set, '_%');

-- This handler will set the value v_finished to 1
-- if there are no more rows

DECLARE CONTINUE HANDLER
FOR NOT FOUND SET v_finished = 1;

OPEN alter_cursor;

-- Start a loop to fetch each rows from the cursor
get_table: LOOP

-- Fetch the table names one by one
FETCH alter_cursor INTO v_table_name;

-- If there is no more record, then we have to skip
-- the commands inside the loop
IF v_finished = 1 THEN
LEAVE get_table;
END IF;

IF v_table_name != '' THEN

IF v_message = 'No records' THEN
SET v_message = '';
END IF;

-- This technic makes the trick, it prepares a statement
-- that is based on the v_table_name parameter and it means
-- that this one is different by each iteration inside the loop

SET @s = CONCAT('ALTER TABLE ',v_table_name,
' CONVERT TO CHARACTER SET ', character_set);
PREPARE stmt FROM @s;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

SET v_message = CONCAT('The table ', v_table_name ,
' was changed to the default collation of ', character_set,
'.\n', v_message);

SET v_table_name = '';

END IF;
-- Close the loop and the cursor
END LOOP get_table;
CLOSE alter_cursor;

-- Returns information about the altered tables or 'No records'
SELECT v_message;

END $$

DELIMITER ;

创建过程后，可以简单地调用它:

CALL changeCollation('utf8');

更多细节请阅读这篇博客。