SQL ?

How can i use sql to save data? i want my player use /cmd item

PHP:

public function onCommand(CommandSender $sender, Command $command, $label, array $args){
          if(count($args) === 0){
              return false;
          }
          $arg = array_shift($args);
          switch($arg){
              case "item":
                  break;
return true;
            }
        }

just one time. Case "item"