条件，如果搜索栏为null则返回错误html

I created a search bar in html that searches my mySQL database and displays the results for my search.

My problem is that if I haven't typed anything on the bar it will display the whole table when I do not want that.

My code is this

<form action="Artists.php" method="post">
    <input type="text" name="searchdatabase"<br><br>
    <input type="submit" name="searching" value="Search"><br><br>

and I am trying to do this

  <?php 

      if( ! mysqli_num_rows($resultsearch) ) {
      echo "Mysql error: " .mysqli_error($mysql); }

      while($row =  mysqli_fetch_array($resultsearch)):?>
          <tr>
              <td><?php echo $row['firstname'];?></td>
              <td><?php echo $row['lastname'];?></td>

          </tr>
  <?php endwhile;?>

But this is not working, I am trying to create an if statement on html (I cant use Javascript) so that my code will not display my entire table and will only display the search I wanted once I press the search button.

Why do you have endwhile? Just use {} for your loop, match your searchdatabase to one of your names in the mysql. If it doesn't appear in the database throw a error. Other wise have it display. Right now you are calling your whole table. $blah = $con, "Select * From somedata where searchdatabase = firstName"; if you need to order by a certain way order by asce or something like that hope that helps.

just make the input as 'required'

 <input type="text" name="searchdatabase" required>

this way you cant leave the search bar unfilled.

</div>