到目前为止，我还没有涉及到用户功能，但根据法典，应该是这样的。

 $args = array(
      \'meta_key\' => \'g300\',
      \'meta_value\' => \',\'
 );

 $users = get_users( $args );

EDIT

Example 2

 $args = array(
      \'meta_key\' => \'g300\',
      \'meta_value\' => \'I will attend the G300 class,\' //Was the comma intentional? If not, remove
 );

 $users = get_users( $args );

 if( !empty( $users ) )
 {
      foreach( $users as $user )
      {
           echo $user->display_name; //name
           echo $user->user_email; //email

           $meta = get_user_meta( $user->ID, \'is_700_a\', TRUE );

           echo $meta; //the meta field value
      }
 }