PHP Loading data from mysql according to time

Question

I am creating a social networking website using PHP and MYSQL. I am facing problem in loading posts of friends and the current user, and arranging them according to the recent. Here is my program, I know this is not a good method but this is what i could manage to code.

<?php
if(isset($_COOKIE["uid"]))
{
    include("includes/functions.php");
    include("includes/config.php");
    $uid=$_COOKIE["uid"];
    $posts=array();
    $friends=array();
    $sql="SELECT * FROM posts WHERE uid='$uid'";
    $result = $conn->query($sql);
    if ($result->num_rows > 0) {
        while($row = $result->fetch_assoc()) {
            $posts[]=[$row["pid"],$row["uid"],$row["post"],$row["time"]];
        }
    }
    $sql="SELECT * FROM friends WHERE uid1='$uid' OR uid2='$uid' AND status='1'";
    $result = $conn->query($sql);
    if ($result->num_rows > 0) {
        while($row = $result->fetch_assoc()) {
            if($uid1==$uid){$friends[]=$uid2;}else{$friends[]=$uid1;}
        }
    }
    for($i=0;$i<count($friends);$i++)
    {
        $temp_uid=$friends[$i];
        $sql="SELECT * FROM posts WHERE uid='$temp_uid'";
        $result = $conn->query($sql);
        if ($result->num_rows > 0) {
            while($row = $result->fetch_assoc()) {
                $posts[]=[$row["pid"],$row["uid"],$row["post"],$row["time"]];
            }
        }
    }
    $eo=0;
    for($i=0;$i<count($posts);$i++)
    {
        echo "Username: ".u2u($posts[$i][1])."<br>Post Message: ".nl2br($posts[$i][2])."<br>Time: ".t2t($posts[$i][3])."<p>";
    }

}
else
{
    echo "error";
}
?>

config.php

<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "evenure";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
?>

functions.php

<?php
function u2u($temp_uid){
    require("../config.php");
    $sql="SELECT username FROM users WHERE uid='$temp_uid'";
    $result = $conn->query($sql);
    if ($result->num_rows > 0) {
        while($row = $result->fetch_assoc()) {
            return $row["username"];
        }
    }
    else
    {
        return "Invalid UID";
    }
}

function t2t($temp_time){
    date_default_timezone_set('Asia/Kolkata');
    $etime = time() - $temp_time;

    if ($etime < 1)
    {
        return '0 seconds';
    }

    $a = array( 365 * 24 * 60 * 60  =>  'year',
                 30 * 24 * 60 * 60  =>  'month',
                      24 * 60 * 60  =>  'day',
                           60 * 60  =>  'hour',
                                60  =>  'minute',
                                 1  =>  'second'
                );
    $a_plural = array( 'year'   => 'years',
                       'month'  => 'months',
                       'day'    => 'days',
                       'hour'   => 'hours',
                       'minute' => 'minutes',
                       'second' => 'seconds'
                );

    foreach ($a as $secs => $str)
    {
        $d = $etime / $secs;
        if ($d >= 1)
        {
            $r = round($d);
            return $r . ' ' . ($r > 1 ? $a_plural[$str] : $str) . ' ago';
        }
    }
}
?>

My above codes work properly but the only problem is I am not able to arrange them according to the recent time, i.e., load new posts first and then old posts.

Answer 1

<?php
if(isset($_COOKIE["uid"]))
{
    include("includes/functions.php");
    include("includes/config.php");
    $uid=$_COOKIE["uid"];
    $posts = [];
    $friends = [];
    $sql="SELECT uid1, uid2 FROM friends WHERE uid1='$uid' OR uid2='$uid' AND status='1'";
    $result = $conn->query($sql);
    if ($result->num_rows > 0) {
        while($row = $result->fetch_assoc()) {
            $friends[$uid1] = $uid1;
            $friends[$uid2] = $uid2; 
        }
    }
    $friends[$uid] = $uid;
    // $friends now contain all friends and person himself

    $friendsSql = implode(', ', $friends);
    $sql="SELECT * FROM posts WHERE uid IN ($friendsSql)' ORDER BY posts.time DESC";
    $result = $conn->query($sql);
    if ($result->num_rows > 0) {
        while($row = $result->fetch_assoc()) {
            $posts[]=[$row["pid"],$row["uid"],$row["post"],$row["time"]];
        }
    }
    // $posts now contain posts of person and his friends in desc order
}