How can I change collation for all tables and columns in MySQL database?
In order to change the collation for all of the tables in certain database you should create a custom script and execute it on the server. 

Here is a sample PHP script:

&lt;?php

$database_name='dbname';
$database_username='dbusername';
$database_password='dbpassword';

$connection = mysql_connect('localhost',$database_username,$database_password);

if(!$connection) {
    echo "Cannot connect to the database – incorrect details";
} else{
    mysql_select_db($database_name);
    $result=mysql_query('show tables');

    while($tables = mysql_fetch_array($result)) {

        foreach ($tables as $key =&gt; $value) {
            mysql_query("ALTER TABLE ".$value." CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci");
        }
    }
echo "Successfull collation change!"; 
}
?&gt;