Converting old script to boolean

[learningcurve]

I am working with an older script that I did not write.  It is working fine, but I want to convert it to a Boolean search.  I am a real newbie and this script seems to have some weirdness that is throwing me in addition to trying to set up a complicated search.  It is at the point where it will do single word searches and searches for items inside quotations, but it is ignoring AND/NOT/OR qualifiers. I have read manuals and searched the web for help on this and I have gotten conflicting information and/or something that didn't work (I think because of the way this query was written).  I feel like the solution will be obvious once I see it, but I am lost in the forest right now...

 

Here is the code:

<?php
if (isset($_GET['words'])) $words = $_GET['words'];
else $words = '';

echo "
<!--div class='searchExamples'>
<h3>Search examples:</h3>
<p><em>apple banana</em> ← find <strong>any</strong> of the words</p>
<p><em>apple <strong>+</strong>banana</em> ← results <strong>must</strong> include <em>banana</em></p>
<p><em>apple <strong>-</strong>banana</em> ← results <strong>can't</strong> include <em>banana</em></p>
<p><em>appl<strong>*</strong></em> ← find <strong>any</strong> word starting with <em>appl</em></p>
<p><em><strong>"</strong>apple juice<strong>"</strong></em> ← find this <strong>exact phrase</strong></p>
</div-->

<p>You can search the titles, authors, and abstracts of every article by entering keywords here:</p>
<form action='search.php' method='get'><p><input name='words' class='textfield' value='$words'><input type='submit' value='Search'><br>(For best results, try using spaces instead of punctuation marks such as hyphens.)</p></form>
<!-- p>To refine your search, see the examples to the right.</p -->";


if (isset($_GET['words'])) {
echo '<h2>Search results:</h2>';
$words = mysql_real_escape_string($_GET['words']);
$query = "SELECT `volume`,`number`,`year`,`title`,`authors`,`abstract`,MATCH (title,authors,abstract) AGAINST ('$words' IN BOOLEAN MODE) AS `score` FROM `articles` WHERE MATCH (title,authors,abstract) AGAINST ('$words' IN BOOLEAN MODE) ORDER BY `score` DESC;";

//error_log($query);
$result = mysql_query($query);

$ip = mysql_real_escape_string($_SERVER['REMOTE_ADDR']);
$dns = mysql_real_escape_string(gethostbyaddr($_SERVER['REMOTE_ADDR']));
global $accountID;
if ($accountID===FALSE) $account = 'NULL';
else $account = '"'.mysql_real_escape_string($accountID).'"';
mysql_query("INSERT INTO `searches` (`timestamp`,`query`,`ip`,`dns`,`account_id`,`results`) VALUES (NOW(),'$words','$ip','$dns',$account,'".mysql_num_rows($result)."');");

if (mysql_num_rows($result)==0) {
	echo '<p>Sorry, your search returned no matches.  Try rephrasing your search words.</p>';
} else {
	$data = array();
	$max = 0;
	while ($row = mysql_fetch_assoc($result)) {
		$data[] = $row;
		$max = max($max,$row['score']);
	}
	echo '<table class="results"><tr><th>Article</th><th>Abstract</th></tr>';
	foreach ($data as $row) {
		$wordsSplit = explode(' ',$words);
		$wordsSplit = array_unique($wordsSplit);
		$title = htmlentities($row['title']);
		$authors = htmlentities($row['authors']);
		$abstract = htmlentities($row['abstract']);
		foreach ($wordsSplit as $thisWord) {
			$aword = preg_replace('|[^a-z]|i','',$thisWord);
			if ($aword!='') {
				$title = preg_replace("|($aword)|i",'<span>\1</span>',$title);
				$authors = preg_replace("|($aword)|i",'<span>\1</span>',$authors);
				$abstract = preg_replace("|($aword)|i",'<span>\1</span>',$abstract);
			}
		}
		if ($abstract=='') $abstract = 'No abstract available';
		echo '<tr><td class="articleInfo"><p class="issue">'.issueString($row['volume'],$row['number'],$row['year']).'</p><p><cite>'.$title.'</cite></p><p>'.$authors.'</p></td><td class="abstract">'.$abstract.'</td></tr>';
	}
	echo '</table>';
}
}
?>