我在这里贡献，正如OP所问的:

如何改变数据库，表，列的排序规则?

所选的答案只是在表级别上陈述它。

在数据库范围内更改:

ALTER DATABASE <database_name> CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

更改每个表:

ALTER TABLE <table_name> CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

好的做法是在表级别更改它，因为它也会更改列。为特定列更改是针对任何特定的情况。

更改特定列的排序规则:

ALTER TABLE <table_name> MODIFY <column_name> VARCHAR(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

你可以运行一个php脚本。

               <?php
                   $con = mysql_connect('localhost','user','password');
                   if(!$con) { echo "Cannot connect to the database ";die();}
                   mysql_select_db('dbname');
                   $result=mysql_query('show tables');
                   while($tables = mysql_fetch_array($result)) {
                            foreach ($tables as $key => $value) {
                             mysql_query("ALTER TABLE $value CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci");
                       }}
                   echo "The collation of your database has been successfully changed!";
                ?>

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

我刚刚编写了一个bash脚本来查找给定数据库中的所有表并隐藏它们(及其列)。

脚本下载地址:https://github.com/Juddling/mysql-charset

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。

生成查询以更新每个表和每个表的列。 我以前在我的一些项目中使用过这种方法，并且能够解决我的大部分COLLATION问题。(特别是在join上)

要使用，只需将结果导出为带分隔符的文本(可能是新行'\n')

每个表

SELECT CONCAT('ALTER TABLE `', TABLE_NAME, 
              '` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;') 
       AS 'USE `DATABASE_NAME`;' 
FROM   INFORMATION_SCHEMA.TABLES 
WHERE  TABLE_SCHEMA = 'DATABASE_NAME' 
       AND TABLE_TYPE LIKE 'BASE TABLE' 

每一列

SELECT CONCAT('ALTER TABLE `', TABLE_NAME, '` MODIFY COLUMN `', COLUMN_NAME,'` ', 
              DATA_TYPE, IF(CHARACTER_MAXIMUM_LENGTH IS NULL 
       OR DATA_TYPE LIKE 'longtext', '', CONCAT('(', CHARACTER_MAXIMUM_LENGTH, 
                                         ')') 
       ), ' COLLATE utf8mb4_unicode_ci;') AS 'USE `DATABASE_NAME`;' 
FROM   INFORMATION_SCHEMA.COLUMNS 
WHERE  TABLE_SCHEMA = 'DATABASE_NAME' 
       AND (SELECT INFORMATION_SCHEMA.TABLES.TABLE_TYPE 
            FROM   INFORMATION_SCHEMA.TABLES 
            WHERE  INFORMATION_SCHEMA.TABLES.TABLE_SCHEMA = 
                   INFORMATION_SCHEMA.COLUMNS.TABLE_SCHEMA 
                   AND INFORMATION_SCHEMA.TABLES.TABLE_NAME = 
                       INFORMATION_SCHEMA.COLUMNS.TABLE_NAME 
            LIMIT  1) LIKE 'BASE TABLE' 
       AND DATA_TYPE IN ( 'char', 'varchar' ) /* include other types if necessary */