摸魚一群人

$conn = new MySQLi("localhost","資料庫帳號","資料庫密碼","資料庫名稱");
if($conn->connect_errno){
    echo mysqli_connect_error();
    exit;
}
$res=$conn->query("show tables") or die($conn->error);
while($tables=$res->fetch_array()){
    $conn->query("ALTER TABLE $tables[0] CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci") or die($conn->error);
}
echo "The collation of your database has been successfully changed!";
$res->free();
$conn->close();

ALTER TABLE [資料表名稱] CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;

ALTER TABLE [資料表名稱] DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;

ALTER DATABASE [資料庫名稱] DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;