MySQL无法授予数据库用户对数据库的权限

Question

我正在创建一个数据库和一个新的数据库用户。我正在尝试将所有权限授予该新创建的数据库用户。

但是我失败了：

• 数据库创建成功
• 数据库用户创建成功
• 但是授予权限失败

它没有显示任何错误。我试图使用新的用户名和密码登录。我可以登录，但是看不到数据库，这意味着授予权限不正确。

请参阅我的代码：

        $username = "bdsat_boishakhi29";
        $password = $username;
        $databasename = $username; 

        $admin_db = "mysql";
        $admin_user = "bdsat";
        $admin_password = "demo123456";

        $connection=mysqli_connect("localhost",$admin_user,$admin_password);

        if (mysqli_connect_errno())
        {
            echo "<br>Failed to connect to MySQL: " . mysqli_connect_error();
        }else{
            echo "<br>Connected XXX";
        } 

        $sql="CREATE DATABASE $databasename";

        if (mysqli_query($connection,$sql))
        {
            echo "<br>Database <b>$databasename</b> created successfully!";
        }
        else
        {
            echo "<br>Error  creating database: " . mysqli_error($connection);
        }

        // Create user 
        $sql="CREATE USER '".$username."'@'localhost' IDENTIFIED BY '".$password."'"; 

        if (mysqli_query($connection,$sql))
        {
           echo "<p>User Created... <b>$databasename</b> created successfully!</p>";
        }
        else
        {
            echo "<br>Error creating database user: " . mysqli_error($connection);
        }


        // Grant user permissions  
        $sql="GRANT ALL PRIVILEGES ON $databasename.* TO $username@'localhost' IDENTIFIED BY $password"; 

        $connection=mysqli_connect("localhost",$admin_user,$admin_password);

        if (mysqli_connect_errno())
        {
            echo "<br>Failed to connect to MySQL: " . mysqli_connect_error();
        }else{
            echo "<br>Connected XXX";
        } 

        if (mysqli_query($sql))
        {
           echo "<p>User permissions Created... <b>$databasename</b> created successfully!</p>";
        }
        else
        {
           echo "<br>Error granting database permission: " . mysqli_error($connection2);
        } 

        echo "<pre>";
        print_r(mysqli_query("SHOW GRANTS FOR $username@'localhost'"));