Updating only the recent post using php and Ajax

Question

i have an ajax script and a php file on the server that inserts new post to the database, the ajax script can post to the target php file and get a response as json data (which is decoded and echo as HTML data which is my posts) which I use to append to a div. however, my solution returns the entire result from my database, ie all my posts that my query returns via mysql_query. how do i get only results that are recent or at least how do i get only my last post;

$(function() {
 $("#PostItemz").on('submit', function(event){
event.preventDefault()
var formData = new FormData(this);

    $.ajax({
        url: 'inc/modules/post_data.php',
        type: 'POST',
        data: formData,
        success: function (data) {
             //here the data return is my post as html object
            //data is return via echo on another php page
           console.log(data);
           $('#postarea').append(data);
           $("#PostItemz")[0].reset();
           $('.inner-addon, .left-addon, .create-text').hide();
        },
        cache: false,
        contentType: false,
        processData: false
    });

});


  });

AND this is my php code: on server that returns the post data:

        <?php
         function getFollowedGroupPosts($user_id){

        $sql_query = mysql_query("SELECT gid FROM members WHERE uid = '$user_id'");
   //iterate through record set, push records into user defined record_set[] array and return array as json encoded data
                        .
                        .
                        .
                        .
                        .
        $record_set[] = array('gid' => $rows_b['gid'],
                    'pid' => $rows_b['pid'],
                    'post' => $rows_b['post'],
                    'images' => getPostImages($rows_b['pid']),
                    'jImages' => $url_string,
                    'videos' => getPostVideos($rows_b['pid']),      
                    'audios' => getPostAudios($rows_b['pid']),
                    'date' => timeAgo($rows_b['date']),
                    'username' => userIdToName($rows_b['uid']),
                    'filemap_id' => $rows_b['filemap_id'],
                    'group_name' => groupIdToName($rows_b['gid']),
                    'comments' => getComments($rows_b['pid']),
                    'likes' => checkLikeCount($rows_b['pid']),
                    'dislikes' => checkDislikeCount($rows_b['pid']),
                    'post_count' => $row_count_b);


    }

        }
        return $record_set;

how do i make async ajax calls to php and what query do i use on server side to return recent posts other than the ones on my page already

Answer 1

For any last inserted record will be get through mysql_insert_id If your table contain any AUTO_INCREMENT column it will return that Value.

<?php
$last_id = mysql_insert_id ( mysqli $link )
SELECT * FROM tbl WHERE pid(your primary key) = '$last_id'
?>

Also you can do that by using limit and order

SELECT * FROM `table_name` 
ORDER BY `table_name`.`column_name` DESC
LIMIT 1 

Note: Do not use mysql It deprecated from php 5.5.x

Answer 2

使用mysqli_insert_id()方法获取最后插入的帖子的主键，然后使用该ID检索该特定帖子并从php脚本返回。