simple php to query a connected database using AJAX. Important: USE OF DO WHILE LOOP!

query.php

<?php

require_once('db_connect.php');

if ($con) {

	$select = $_POST['select'];
	$from   = $_POST['from'];
	$where  = $_POST['where'];
	$where_param = $_POST['where_param'];
	
	//strip of trailing or leading whitespace
	$where_param = trim($where_param);

	//only match letters in the given paramter one or more times
	preg_match("([a-zA-Z]+)", $where_param, $matches);
	
	//if $where_param isn't empty...
	if (strlen($where_param) != 0) {
		
		//use it in the query
		$query = "SELECT $select FROM $from WHERE $where='" . $matches[0] . "'";
	}
	
	//otherwise omit
	else {
		$query = "SELECT $select FROM $from";
	}
	
	//DEBUGGING ONLY
	echo $query;
	
	//query the database
	$result = mysql_query($query);
}
else {
	die("Connection is False");
}

echo "<div class='columns'><ul>";

//if the syntax was correct for the query...
if ($result) {
	
	//first check to see if anything was returned from the database
	if ($arr = mysql_fetch_array($result)) {
		
		//if it was, then return the first element of the query resource...
		do {
				
			//DEBUG; dump the var for now
			echo var_dump($arr);
		
		//as long as there are more elements in the resource...
		} while ($arr = mysql_fetch_array($result));
	}
	
	//nothing matched the query
	else {	
		echo 'No matches to your query...';
	}
}
else {
	echo 'Unkown Query Syntax...';
}

//close the html returned
echo "</ul></div>";

?>