从另一个表中选择日期

Question

I really need your help. Please help me out to get this to work.

I have these two tables, the relation between them is the user_id . I accomplished to select who I follow and to display their images into my wall. However, I have this strange issue: the photos are sorted by DESC as i want, but they are sorted by the user_id . This means that whoever I follow first, their image will be sorted first by DESC .

I tried almost every possible way to get the photos to be sorted base on DESC newest photo as the top, but I couldn't. Here are my tables and i'll show you every possible thing I tried:

CREATE TABLE IF NOT EXISTS `photos` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `img` varchar(255) NOT NULL,
  `about` text NOT NULL,
  `date` varchar(222) NOT NULL,
  `user_id` varchar(255) NOT NULL,
  `likes` int(255) NOT NULL,
  `down` int(255) NOT NULL,
  PRIMARY KEY (`id`)
) ;

CREATE TABLE IF NOT EXISTS `follow` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `followers` varchar(255) NOT NULL,
  `following` varchar(255) NOT NULL,
  PRIMARY KEY (`id`)
}

One

followers_photo.php, where I retrieve the following id from:

$the_user = mysql_query("SELECT * FROM users WHERE username = '$getuser'");
$tuser=mysql_fetch_array($the_user);
$tu_id = $tuser['id'];

$followers = mysql_query("SELECT distinct follow.*    
 FROM follow JOIN photos ON (follow.followers  = $tu_id)
order by photos.date DESC");
$f_s_count = mysql_num_rows($followers);    

• index.php which i display the images here.

while($uim = mysql_fetch_assoc($followers)){ $i_id = $uim['following']; $followers_image = mysql_query("SELECT distinct photos.* FROM photos JOIN follow ON (photos.user_id = $i_id) GROUP BY RAND() order by date DESC");

---

The above is working, but as I mentioned it sorts the images based on date DESC and the user_id which I don't want. I want it to stop sorting the image based on the user_id

Two

followers_photo.php

    $the_user = mysql_query("SELECT * FROM users WHERE username = '$getuser'");
$tuser=mysql_fetch_array($the_user);
$isuser = mysql_num_rows($the_user);

$tu_id = $tuser['id'];
$tu_name =$tuser ['username'];
////users whos following Me
$followers = mysql_query(" SELECT distinct follow.* FROM photos join  follow on  follow.followers = photos.user_id WHERE follow.followers = $tu_id order by photos.date DESC");
//
$f_s_count = mysql_num_rows($followers);

---

index.php

    while($uim = mysql_fetch_assoc($followers)){
$i_id = $uim['following'];
$followers_image = mysql_query("SELECT * FROM photos  WHERE user_id = '$i_id' order by date DESC ");

The above does the same as in the first step. Could anyone point me to the right way? Sort the photos from the people I follow based on date DESC , who posts last comes first. Thanks guys, I appreciate your help a lot. And sorry for my bad English.

Update

now with the solution that vegatripy give , images are duplicating and not order as wanted. on left is what is showing now. what i want is to sort as the right image. any ideas? http://i.stack.imgur.com/Cod6z.jpg

Solved

    $followers = mysql_query("SELECT PHOTOs.IMG, follow.followers, follow.following, photos.date,photos.img,photos.likes,photos.down,photos.id,photos.about
FROM FOLLOW
JOIN PHOTOs ON ( PHOTOs.USER_ID = FOLLOW.FOLLOWING ) 
WHERE FOLLOW.FOLLOWERS =31
ORDER BY PHOTOs.DATE DESC");
$f_s_count = mysql_num_rows($followers);
while($fimage = mysql_fetch_assoc($followers)){
$i_id = $fimage['following'];
$disimg = $fimage['img'];
$disid = $fimage['id'];
$distime = $fimage['date'];
$i_like=$fimage['likes'];
$i_unlike=$fimage['down'];

Answer 1

You're mixing the JOIN with the missing WHERE clause in your sentences (and that's why you used the DISTINCT , because there's no join condition at all and you had repeated rows)

 $followers = mysql_query("SELECT distinct follow.* FROM follow JOIN photos ON (follow.followers = $tu_id) order by photos.date DESC"); 

Which is equivalent to:

$followers = mysql_query("SELECT distinct follow.*
FROM follow, photos WHERE (follow.followers  = $tu_id)
order by photos.date DESC");

That join is giving you the whole cartesian product ( FROM follow JOIN photos ) where column follow.followers = $tu_id , that includes not truly joined rows between "follow" and "photos" tables . To discard rows, you'll need the where clause AFTER the join codition .

Anyway, you're mixing things a little bit. I've analyzed your code several times and I don't get why you are joining "photos" with "follow" tables, when you're selecting columns and using the where condition from just one of them.

I'm going to set an example of what you're trying to do. Just the SQL meaningful stuff. I'll let the PHP to you. These are the tables USERS, PHOTO and FOLLOW

USERS:
ID      USERNAME
--      --------
01      John
02      Smith
03      Rambo

PHOTO: (just the relevant columns)
ID      IMG     DATE            USER_ID  
--      -----   -----------     ------- 
01      a.jpg   01-02-2013      03  (Rambo)
02      b.jpg   30-07-2013      03  (Rambo)
03      c.jpg   04-04-2012      02  (Smith)
04      d.jog   04-04-2013      01  (John)

FOLLOW:
ID      FOLLOWERS   FOLLOWING
--      --          --
01      01          02      (John is following Smith)
02      01          03      (John is following Rambo)
03      02          01      (Smith is following John)
04      03          01      (Rambo is following John)
05      02          03      (Smith is following Rambo)

With this set up, we want to display the images from the users of a given username is following, order by date of image. So, the given username is "John". That is ID "01". If we just need the images from the people that John is following, then:

SELECT PHOTO.IMG 
FROM FOLLOW JOIN PHOTO ON (PHOTO.USER_ID = FOLLOW.FOLLOWING) 
WHERE FOLLOW.FOLLOWERS = 01
ORDER BY PHOTO.DATE DESC;

We are joining "Photo.User_ID" with "Follow.following", order by date desc. This will make a temp table like:

PHOTO.ID    PHOTO.IMG   PHOTO.DATE  PHOTO.USER_ID   FOLLOW.ID   FOLLOW.FOLLOWERS    FOLLOW.FOLLOWING
--          -----       ----------  -------         --          --                  --
02          b.jpg       30-07-2013  03  (Rambo)     02          01                  03      (John is following Rambo)
04          d.jog       04-04-2013  01  (John)      04          03                  01      (Rambo is following John)
04          d.jog       04-04-2013  01  (John)      03          02                  01      (Smith is following John)
01          a.jpg       01-02-2013  03  (Rambo)     02          01                  03      (John is following Rambo)
03          c.jpg       04-04-2012  02  (Smith)     01          01                  02      (John is following Smith)

Then the WHERE clause will select only those rows where the follower is the user_id we want (01). That's:

PHOTO.ID    PHOTO.IMG   PHOTO.DATE  PHOTO.USER_ID   FOLLOW.ID   FOLLOW.FOLLOWERS    FOLLOW.FOLLOWING
--          -----       ----------  -------         --          --                  --
02          b.jpg       30-07-2013  03  (Rambo)     02          01                  03      (John is following Rambo)
01          a.jpg       01-02-2013  03  (Rambo)     02          01                  03      (John is following Rambo)
03          c.jpg       04-04-2012  02  (Smith)     01          01                  02      (John is following Smith)

So as John we will see 2 photos from Rambo and 1 from Smith. Ordered by date.

Hope this help you.