combine two querys with join

Question

after many hints here I tried it to combine the following two querys. I think the code is self explaining.

the tables:

comments: id(INT), username(VARCHAR), autorpost(TEXT), comment(TEXT), id_post(INT), time(TIME)

posts: id(INT), autorid(INT), autor(TEXT), date(DATE), longitude(FLOAT), latitude(FLOAT), title(TEXT), text(TEXT), town(TEXT), time(TIME)

    $hostname='localhost';
            $user='root';
            $password='';
            $useron = $_COOKIE['username'];
                    try {
                            $dbh = new PDO("mysql:host=$hostname;dbname=searchfood",$user,$password);

                            $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); // <== add this line
                             $sql = "SELECT id_post 
    FROM comments 
    WHERE username = '$useron'
    ORDER BY id DESC"; // oder (longitude between $loo and $lo or latitude  between $laa and $la) versuchen
      if ($own = $dbh->query($sql)) {// need to add this line in your code
          // then after fetchColumn
         $ownco = $own->fetchAll(PDO::FETCH_COLUMN, 0);      
       }                        
                    }
                    catch(PDOException $e)
                    {
                            echo $e->getMessage();
                    }  


                    try {
                            $dbh = new PDO("mysql:host=$hostname;dbname=searchfood",$user,$password);

                            $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); // <== add this line
                             $sql = "SELECT  id, autorid, autor, date, longitude, latitude, title, text, town, time
FROM posts 
 WHERE id in (" . implode(",",$ownco) . ")
    ORDER BY id DESC"; // oder (longitude between $loo and $lo or latitude  between $laa and $la) versuchen
      if ($resco = $dbh->query($sql)) {// need to add this line in your code
          // then after fetchColumn
         $resultcom = $resco->fetchAll();        
       }                        
                    }
                    catch(PDOException $e)
                    {
                            echo $e->getMessage();
                    }    

My own try:

"SELECT posts.id, posts.autorid, posts.autor, posts.date, posts.longitude, posts.latitude, posts.title, posts.text, posts.town, posts.time, comments.id_post 
FROM posts 
INNER JOIN
comments
WHERE id = post_id
ORDER BY id DESC"

Answer 1

Try this query

"SELECT p.*, c.id_post
FROM posts p
JOIN comments c ON( c.id_post = p.id)
ORDER BY p.id DESC"