<?php
         
 $db_spojeni= mysqli_connect('localhost', 'acerr' , '****' , 'promene', 3306);
         
 if(!$db_spojeni){
  die('Chyba');
 }
         
 $objekt_vysledku = mysqli_query($db_spojeni , 'SELECT a  FROM promena');
  
 if (!$objekt_vysledku){
  die ('Chyba');
 }
            
     
    while ($radek = mysqli_fetch_array($objekt_vysledku))
    {
    $a = $radek['a'];
    }
     
    $b=$a+1;
    $tb="promena";
    $zmena=mysql_query("UPDATE `$tb` SET `a` = `$a` WHERE `a` = `$b` , $db_spojeni");
     
     
    while ($radek = mysqli_fetch_array($objekt_vysledku))
    {
  $a = $radek['a'];
    }
     
     
     
    if ($a==1)
    echo 'alda je supr';
     
    echo $a
 ?>