How to get a session value from a second table? - php

Question

I have two tables for the users; a login table and the user profile table.
I want to compare a value from 'userprofiletable' to another value from another table called posts. If the value is equal, it shows a list.
I have the following code. The problem is that it is not comparing the value in the posts table with the value of the session from user profile table.
Could someone help me please?
<?php
$limit = '5';
$dbreq = 'SELECT * FROM `posts` ORDER BY `pos` DESC';
$dbdata = mysql_query($dbreq);
while($dbval = mysql_fetch_array($dbdata))
{
if (($dbval['city'] == $_SESSION['student_city'])) { //checks for last 4 accomodation
if ($limit >= '1') {
echo '<tr><td>'.$dbval['title'].'</td></tr>';
$limit = $limit -'1';
}
}
}
?>
I also want to get the value of userprofiletable and post it in the posts table. For example, when somebody make a new post.

Answer 1

Your post is a bit unclear, but I think this is what you want:
<?php
$userid = 11542;//Sample uid. You will have to figure this out and set it.
$limit = 5;
$dbreq = "SELECT * FROM `posts` WHERE `userid`=".$userid." ORDER BY `pos` DESC LIMIT=".$limit.";";
$dbdata = mysql_query($dbreq);
while($dbval = mysql_fetch_array($dbdata))
{
if (($dbval['city'] == $_SESSION['student_city'])) { //checks for last 4 accomodation
echo '<tr><td>'.$dbval['title'].'</td></tr>';
}
}
?>

Answer 2

The question is not clear, but there could be two answers:
To reproduce your code, you can do in ONE sql query:
$dbreq = 'SELECT *
FROM `posts`
WHERE city="'.mysql_real_escape_string($_SESSION['student_city']).'"
ORDER BY `pos` DESC
LIMIT 4';
If, however, there are two tables, then you need "LEFT JOIN" linking the posts table to the userprofile table
$dbreq = 'SELECT p.*, u.*
FROM posts p
LEFT JOIN userprofiletable up ON p.UserID=up.UserID
WHERE up.city="'.mysql_real_escape_string($_SESSION['student_city']).'"
ORDER BY p.pos DESC
LIMIT 4';
(UserID in the table above is the name of the field in the posts table and userprofiletable that links the two.)