$value = "a";
$sql = "select * from characters";
$query = mysql_query($sql);
$fetch = mysql_fetch_array($query);
 
for ($i = 0; $i < 30; $i++) {
  if($value == $fetch['letters']) {
    $counter++;
  }
}
echo $counter;

Im confused now I cant think of the logic on how to check 30 repeated rows each time.

$sql = "select * from characters where letters like '%a%'";
$query = mysql_query($sql);
$count=mysql_num_rows($query);
echo $count;

$variable="a";
$sql = "select * from characters where letters like '%".$variable."%'";