PHP Search

<?phpinclude('page_parts/header.php');$submit = $_POST["submit"];$keywords = $_POST["keywords"];if(isset($submit) || isset($keywords)){doSearch($keywords);}else{getKeywords();}	function getKeywords(){?><form name="frmKW" action="search.php" method="post"><h1 class="search_header">Search</h1>Keywords:<input type="text" name="keywords" maxlength="100"><br><br><input type="submit" name="submit" value="Search"></form><?php}	function doSearch($search_keywords){		$arrWords = explode(" ", $search_keywords);		if(sizeof($arrWords) == 0 || $search_keywords == ""){			echo "You didn't enter any keywords<br>";			echo "<a href='search.php'>Go Back</a>";		} else {		 	for($i = 0; $i < sizeof($arrWords); $i++){				$result = mysql_query("select articleIds from searchWords where word = '".(string)$arrWords[$i]."'");				 if(mysql_num_rows($result) > 0){					// Get the id's of the articles					$j=0;					while($row1 = mysql_fetch_array($result)){						$arrIds[$j]=$row1[0];						$j++;					}					//$arrIds = explode(",", $row[0]);					$arrWhere = implode(" OR aid = ", $arrIds);					$aQuery = "select aid, title, summary from articles where aid = " . $arrWhere;					$aResult = mysql_query($aQuery);					$count = 0;					$articles = array();					if(mysql_num_rows($aResult) > 0){						while($aRow = mysql_fetch_array($aResult)){							$articles[$count] = array (								"aid" => $aRow["aid"],								"title" => $aRow["title"],								"summary" => $aRow["summary"]							);							$count++;						}					}					if(isset($articles)){						//$articles = array_unique($articles);						echo "<h1 class=\"search_header\">" . sizeof($articles);						echo (sizeof($articles) == 1 ? " article" : " articles");						echo " found:</h1>";						foreach($articles as $a => $value){?><a class="search_title" href="articles.php?aid=<?php echo $articles[$a]["aid"]; ?>"><b><u><?php echo $articles[$a]["title"]; ?></u></b></a><br><span class="summary_text"><?php echo $articles[$a]["summary"] . "..."; ?></span><br><a class="search_link" href="articles.php?aid=<?php echo $articles[$a]["aid"]; ?>">http://www.infraterra.net/articles.php?aid=<?php echo $articles[$a]["aid"]; ?></a><br><br><?php}}}else{echo "No results found for '$search_keywords'<br>";echo "<a href='search.php'>Go Back</a>";}}}}include("page_parts/nav.php");include("page_parts/footer.php");?>