SQL Query: Incrementing by two instead of 1

Question

I am trying to update a field in a table by increasing its integer value by 1. Here is what I am using:

function updateViews($id){

$sql = "UPDATE tweets SET tweet_views = tweet_views + 1 WHERE tweet_key = '$id'";

$result = mysql_query($sql) or die("DB Error : ". mysql_error());

return $result;

}

However, I find its incrementing by 2 each time rather than 1? What am I doing wrong?

Thanks

Update

From the answers the SQL is correct. Do you think this may be affected by the rewrite engine??? I ask because I am 100% sure this doesn't run twice or that I don't make the call since there are two scripts. One that calls the function and one that holds the function! This is confusing.

Update 2

Using the debug function. I get this output:

array(4) {
  ["file"]=>
  string(35) "/home/magic/public_html/dbUpdate.php"
  ["line"]=>
  int(16)
  ["function"]=>
  string(15) "myDebugFunction"
  ["args"]=>
  array(0) {
  }
}

array(4) {
  ["file"]=>
  string(31) "/home/magic/public_html/view.php"
  ["line"]=>
  int(10)
  ["function"]=>
  string(11) "updateViews"
  ["args"]=>
  array(1) {
    [0]=>
    &string(5) "7jjdd"
  }
}

It looks as if the script is being called once but it is still getting updated twice??? HELP! :(

Also from the Log file, it looks as if the scripts are being called three times??

13:16:28 id:4a6c9d7cf38016.29304000
  _SERVER[REQUEST_URI]=/lucic
  _SERVER[REDIRECT_URL]=/lucic
  /home/magic/public_html/dbUpdate.php@16 :myDebugFunction
  /home/magic/public_html/view.php@10 :updateViews
13:16:30 id:4a6c9d7eaf93e3.88114161
  _SERVER[REQUEST_URI]=/lucic
  _SERVER[REDIRECT_URL]=/lucic
  /home/magic/public_html/dbUpdate.php@16 :myDebugFunction
  /home/magic/public_html/view.php@10 :updateViews
13:16:31 id:4a6c9d7f846557.12618673
  _SERVER[REQUEST_URI]=/lucic
  _SERVER[REDIRECT_URL]=/lucic
  /home/magic/public_html/dbUpdate.php@16 :myDebugFunction
  /home/magic/public_html/view.php@10 :updateViews

UPDATE 3

Here is the contents of my htaccess file which may be causing a problem.

# REWRITE DEFAULTS
RewriteEngine On
RewriteBase /

RewriteCond %{HTTP_HOST} ^www\.mysite\.com$ [NC]
RewriteRule ^(.*)$ http://mysite.com/$1 [R=301,L]

# /view.php?t=h5k6 externally to /h5k6
RewriteCond %{THE_REQUEST} ^GET\ /view\.php
RewriteCond %{QUERY_STRING} ^([^&]*&)*t=([^&]+)&?.*$
RewriteRule ^view\.php$ /%2? [L,R=301]

# /h5k6 internally to /view.php?t=h5k6
RewriteRule ^([0-9a-z]+)$ view.php?t=$1 [L]

Answer 1

You are running the query more than once by mistake. :)

(ok, thats just a guess, but I'd suggest some logging to make sure)

Answer 2

You can test whether your function is called twice or your script with some debug logging.

function myDebugFunction() {
  static $iid = null;

  if ( is_null($iid) ) {
    $iid = uniqid('', true);
  }

  $log = date('H:i:s').' id:'.$iid."\n".
    "  _SERVER[REQUEST_URI]=". @$_SERVER['REQUEST_URI']."\n" .
    "  _SERVER[REDIRECT_URL]=". @$_SERVER['REDIRECT_URL'];
  foreach(debug_backtrace() as $bt) {
    echo '<pre>'; var_dump($bt); echo '</pre>';
    $log .= "\n  ".$bt['file'].'@'.$bt['line'].' '.@$bt['class'].':'.$bt['function'];
  }
  $log .= "\n";
  error_log($log, 3, 'mydebug.log');
}

function updateViews($id) {
  myDebugFunction();
  $sql = "
    UPDATE
      tweets
    SET
      tweet_views = tweet_views + 1
    WHERE
      tweet_key = '".mysql_real_escape_string($id) ."'
  ";
  $result = mysql_query($sql) or die("DB Error : ". mysql_error());
  return $result;
}

If you find the same id twice in mydebug.log the function has been called twice (within the same php instance). Otherwise your script has been invoked twice.