$query = 'SELECT post.id, post.url, post.image, post.headline, menu.reference as ref, menu.title as name 
FROM post LEFT JOIN menu ON post.category = menu.categorie 
WHERE menu.reference = "'.$grup.'" ORDER BY post.id DESC LIMIT 12 OFFSET '.$offset.'';

$count = 'SELECT COUNT(*) as quantity 
FROM post JOIN menu ON post.category = menu.categorie 
WHERE menu.reference = "'.$grup.'"';