Beastly AJAX SQL WordPress stuff

fml.php

<?php
//////////////////////////////////////////////////////////////
// Ajax Project
/////////////////////////////////////////////////////////////

add_action( 'wp_ajax_nopriv_myajax-submit', 'ajax_project_load' );
add_action( 'wp_ajax_myajax-submit', 'ajax_project_load' );
 
function ajax_project_load() {
    $the_slug = $_POST['slug'];
    $args=array(
      'name' => $the_slug,
      'post_type' => 'projects',
      'post_status' => 'publish',
      'showposts' => 1,
      'ignore_sticky_posts' => 1
    );
    $my_posts = get_posts($args);
    if( $my_posts ) :
    
        global $post, $postCapabilityFilter, $postFocusFilter;
        $post = $my_posts[0]; 
        
        $postCapabilityFilter = $_POST['capFilter']=='undefined'? '' : substr($_POST['capFilter'], 1);
        $postCapabilityFilter =  ereg_replace("[^A-Za-z0-9\-]", "", $postCapabilityFilter );
        
        $postFocusFilter = $_POST['focFilter']=='undefined'? '' : substr($_POST['focFilter'], 1);
        $postFocusFilter =  ereg_replace("[^A-Za-z0-9\-]", "", $postFocusFilter );

        $response = json_encode( "Success" );
        header( "Content-Type: application/json" );	
?>
        
		<div id="ajax-project-<?php the_ID(); ?>" <?php post_class('project main ajax clearfix'); ?> >
			<div class="projectHeader">
				<div class="projectNav clearfix">		
                
<?php
function filtered_adjacent_post($prev_next){
    global $wpdb, $post, $postCapabilityFilter, $postFocusFilter;

    $the_ID = $post->ID;
    $querystr = "
        SELECT $wpdb->postmeta.*, $wpdb->posts.post_name
        FROM $wpdb->posts, $wpdb->postmeta, $wpdb->terms, $wpdb->term_relationships
        WHERE $wpdb->posts.post_type = 'projects' 
        AND $wpdb->posts.post_status = 'publish' 
        AND $wpdb->posts.ID ";
        $querystr .= $prev_next=='next'? "< $the_ID" : "> $the_ID";
        $querystr .= "\n" . "AND $wpdb->posts.ID = $wpdb->postmeta.post_id";
        if ($postCapabilityFilter != ''){ // Capability Filter Set
            $querystr .= "\n" . "AND $wpdb->postmeta.meta_value LIKE '%" . $postCapabilityFilter . "%'";
        }elseif ($postFocusFilter != ''){ // Focus Filter Set
            $querystr .= "\n" . "AND $wpdb->term_relationships.object_id = $wpdb->posts.ID";
            $querystr .= "\n" . "AND $wpdb->term_relationships.term_taxonomy_id = $wpdb->terms.term_id";
            $querystr .= "\n" . "AND $wpdb->terms.slug = '$postFocusFilter'";
        }
        $querystr .= "\n" . "ORDER BY $wpdb->posts.ID DESC";
    $nextProjQuery = $wpdb->get_results($querystr, OBJECT);
//print_r( $nextProjQuery);
//echo $querystr;
    if (!$nextProjQuery){ // Loop if no more projects
        $querystr = "
            SELECT wp_postmeta.*, wp_posts.post_name
            FROM $wpdb->posts, $wpdb->postmeta, $wpdb->terms, $wpdb->term_relationships
            WHERE wp_posts.post_type = 'projects' 
            AND wp_posts.post_status = 'publish' 
            AND wp_posts.ID = wp_postmeta.post_id";
            if ($postCapabilityFilter != ''){ // Capability Filter Set
                $querystr .= "\n" . "AND $wpdb->postmeta.meta_value LIKE '%" . $postCapabilityFilter . "%'";
            }elseif ($postFocusFilter != ''){ // Focus Filter Set
                $querystr .= "\n" . "AND $wpdb->term_relationships.object_id = $wpdb->posts.ID";
                $querystr .= "\n" . "AND $wpdb->term_relationships.term_taxonomy_id = $wpdb->terms.term_id";
                $querystr .= "\n" . "AND $wpdb->terms.slug = '$postFocusFilter'";
            }
            $querystr .= "\n" . "ORDER BY wp_posts.ID ";
        if($prev_next == 'next') {
            $querystr .= "DESC";
        }else{
            $querystr .= "ASC";
        }
        $nextProjQuery = $wpdb->get_results($querystr, OBJECT);
    }
    $nextProject = $nextProjQuery[0];
    $next_slug = $nextProject->post_name;
    return $next_slug;
}

$next_slug = filtered_adjacent_post('next');
$prev_slug = filtered_adjacent_post('prev');

$nextPrevFilter = '';
if ($postCapabilityFilter != ''){
    $nextPrevFilter .= "_$postCapabilityFilter";
}elseif ($postFocusFilter != ''){
    $nextPrevFilter .= "_$postFocusFilter";
}
?>
                    
					<div class="next <?php if(!$next_slug) echo 'inactive';?>">	
						<?php if($prev_slug !='') : ?>
							<a href="#<?php echo $prev_slug . $nextPrevFilter ;?>" onClick="nextPrevProject('<?php echo $prev_slug; ?>');">Previous</a>
						<?php endif; ?>
					</div>
					<div class="previous <?php if(!$prev_slug) echo 'inactive';?>">	
						<?php if($next_slug != '') : ?>
							<a href="#<?php echo $next_slug . $nextPrevFilter ;?>" onClick="nextPrevProject('<?php echo $next_slug; ?>');">Next</a>
						<?php endif; ?>
					</div>	
					<div class="closeBtn">	
						<a href="#">Close Project</a>
					</div>				
                     
				</div> 
			</div>

<!-- ...more stuff below... -->