PHP MySQL Select

           
 <html><body>
 <?php
  $host     = "undcemmysql.mysql.database.azure.com";
  // Initialize MySQLi.
  $conn     = mysqli_init( );
  // Create an SSL connection.
  mysqli_ssl_set( $conn, NULL, NULL, "DigiCertGlobalRootCA.crt.pem", NULL, NULL );
  // Open a new connection to the MySQL server.
  mysqli_real_connect( $conn, $host, "user.id", "passwd", "schema", 3306 );

  $action =  Drop    Create & populate 
             Select ( $course = "" ) 
  if ( $action == "Drop" ) {
    // Drop tables Enrollments and Courses.
    mysqli_query( $conn, "DROP TABLE  Enrollments, Courses" );
    echo "Tables Enrollments and Courses dropped";
  }
  elseif ( $action == "Create & populate" ) {
    // Create and populate table Courses.
    $query = "CREATE TABLE  Courses (
              number CHAR( 10 )  PRIMARY KEY,
              name   VARCHAR( 16 ) ) ENGINE=InnoDB";
    mysqli_query( $conn, $query );

    $query = "INSERT INTO  Courses  VALUES
      ( '457', 'E-Commerce' ), ( '260', 'Web Programming' )";
    mysqli_query( $conn, $query );
    echo "Table Courses created and populated";

    // Create and populate table Enrollments.
    $query = "CREATE TABLE  Enrollments (
              name    VARCHAR( 32 ),
              course  CHAR( 10 ),
              PRIMARY KEY ( name, course ),
              FOREIGN KEY ( course ) REFERENCES  Courses ( number ) )
                ENGINE=InnoDB";
    mysqli_query( $conn, $query );

    $query = "INSERT INTO Enrollments VALUES ('Bart','260'),
            ('Bart','457')";
    mysqli_query( $conn, $query );
    $query = "INSERT INTO Enrollments SELECT 'Ben', number FROM Courses
              WHERE  name = 'E-Commerce'";
    mysqli_query( $conn, $query );
    echo "Table Enrollments created and populated";
  }
  elseif ( $action == "Select" ) {
    $query = "SELECT  E.name student,  C.name course
      FROM   Enrollments E, Courses C
      where  E.course  like  '%$course%' and E.course = C.number";
    $result = mysqli_query( $conn, $query );
    $row    = mysqli_fetch_assoc( $result );
    if ( mysqli_num_rows( $result ) > 0 )
      do
        echo $row['student'] . " 🠞 " . $row['course'];
      while( $row = mysqli_fetch_assoc( $result ) );
    else
      echo "Error selecting enrollments: " . mysqli_connect_error( );
  }
  mysqli_close( $conn );

 ?>
 </body></html>