ID number doesn't change - php

Question

I've been creating a CMS blog and this is one of the pages that accessible by the admins. I'm trying to implement pagination in it.
As you can see, it shows the latest six posts in the first page with the IDs from 1 to 6, but when I click on the forward button, it shows the IDs 1 and 2 again for the other posts in which it should be 7 and 8. Could someone tell me what's causing this bug?
First page
Second page
<!-- Right Side Area Start -->
<div class="col-lg-10">
<div class="card-body bg-info">
<h2 class="large-georgia-white-bold">Top Posts</h2>
</div>
<table class="table table-striped table-hover">
<thead class="thead-dark small-times-white">
<tr>
<th>No.</th>
<th>Title</th>
<th>Date&Time</th>
<th>Author</th>
<th>Comments</th>
<th>Details</th>
</tr>
</thead>
<?php
$SrNo = 0;
global $ConnectingDB;
// Query When Pagination is Active i.e Dashboard.php?page=1
if (isset($_GET["page"])) {
$Page = $_GET["page"];
if ($Page==0||$Page<0) {
$ShowPostFrom=0;
}else{
$ShowPostFrom=($Page*6)-6;
}
$sql ="SELECT * FROM posts ORDER BY id desc LIMIT $ShowPostFrom,6";
$stmt=$ConnectingDB->query($sql);
}
// The default SQL query
else{
$sql = "SELECT * FROM posts ORDER BY id desc LIMIT 0,6";
$stmt=$ConnectingDB->query($sql);
}
while ($DataRows=$stmt->fetch()) {
$PostId = $DataRows["id"];
$DateTime = $DataRows["datetime"];
$Author = $DataRows["author"];
$Title = $DataRows["title"];
$SrNo++;
?>
<tbody class="small-times-black">
<tr>
<td><?php echo $SrNo; ?></td>
<td><?php echo $Title; ?></td>
<td><?php echo $DateTime; ?></td>
<td><?php echo $Author; ?></td>
<td>
<?php $Total = ApproveCommentsAccordingtoPost($PostId);
if ($Total>0) {
?>
<span class="badge badge-success">
<?php
echo $Total; ?>
</span>
<?php } ?>
<?php $Total = DisApproveCommentsAccordingtoPost($PostId);
if ($Total>0) { ?>
<span class="badge badge-danger">
<?php
echo $Total; ?>
</span>
<?php } ?>
</td>
<td> <a target="_blank" href="FullPost.php?id=<?php echo $PostId; ?>">
<span class="btn btn-info">Preview</span>
</a>
</td>
</tr>
</tbody>
<?php } ?>
</table>
<!-- Right Side Area End -->
<!-- Pagination -->
<nav>
<ul class="pagination pagination-lg">
<!-- Creating Backward Button -->
<?php if( isset($Page) ) {
if ( $Page>1 ) {?>
<li class="page-item">
«
</li>
<?php } }?>
<?php
global $ConnectingDB;
$sql = "SELECT COUNT(*) FROM posts";
$stmt = $ConnectingDB->query($sql);
$RowPagination = $stmt->fetch();
$TotalPosts = array_shift($RowPagination);
//echo $TotalPosts."<br>";
$PostPagination=$TotalPosts/6;
$PostPagination=ceil($PostPagination);
//echo $PostPagination;
for ($i=1; $i <= $PostPagination ; $i++) {
?>
<li class="page-item">
<?php echo $i; ?>
</li>
<?php } ?>
<!-- Creating Forward Button -->
<?php if ( isset($Page) && !empty($Page) ) {
if ($Page+1 <= $PostPagination) {?>
<li class="page-item">
»
</li>
<?php } }?>
</ul>
</nav>
</div>
</div>
</section>
<!-- Main area end -->

Answer 1

Your script always reassigns $SrNo = 0 when the page is loaded and starts over. You should add the page * 6 value to it so it becomes aware of the offset. In fact, you're already using that logic for $ShowPostFrom, so you can simply assign the same value to $SrNo and it should work:
if ($Page==0||$Page<0) {
$ShowPostFrom=0;
}else{
$ShowPostFrom=($Page*6)-6;
}
$SrNo = $ShowPostFrom; // <- this is what you should add
If you don't mind modifying $ShowPostFrom, you can drop $SrNo completely and just use $ShowPostFrom to show the number.