PHP Pagination of MySQL Query not incrementing/decrementing properly - php

Question

I'm having trouble with the follow PHP which paginates the results of a MySQL query.
When I go to webpagename.php with the first page of the results and click Previous, the browser changes to webpagename.php?page=-1 and shows the first page of results again. If I click Previous again, it changes to webpagename.php?page=-2 and shows Page 1 of the results again, etc.
When I go to webpagename.php with the first page of the results and click Next, the browser changes to webpagename.php?page=1 and shows the first page of results again. I then have to hit Next a second time to move to Page 2.
When I go to the last page of the results - Page 8 - and click Next, the browser changes to webpagename.php?page=9 and shows Page 1 of the results. If I click Next again, it shows webpagename.php?page=10 and shows Page 1 of the results again, etc.
Expected Results:
When on Page 1 and a user hits Previous, I would like the code to do nothing/not decrement. When on Page 8 - the last page of results, I would like the code to do nothing/not increment. Of course, I would also expect that if you hit Next from Page 1 that it doesn't display Page 1 a second time but rather goes to Page 2.
Your exact changes to this code to make it work properly are very much appreciated. Thank you for time.
<?php
mysql_connect("localhost","username","password") or die(mysql_error());
mysql_select_db("dbname") or die(mysql_error());
// number of results to show per page
$per_page = 10;
// figure out the total pages in the database
$result = mysql_query("SELECT * FROM uc_users LEFT JOIN ent_dancers ON uc_users.id = ent_dancers.id WHERE ent_dancers.DancerYesNo = '1' AND ent_dancers.DancerEnabledYesNo = '1' ORDER BY uc_users.display_name ASC");
$total_results = mysql_num_rows($result);
$total_pages = ceil($total_results / $per_page);
// check if the 'page' variable is set in the URL (ex: webpagename.php?page=1)
if (isset($_GET['page']) && is_numeric($_GET['page']))
{
$show_page = $_GET['page'];
// make sure the $show_page value is valid
if ($show_page > 0 && $show_page <= $total_pages)
{
$start = ($show_page -1) * $per_page;
$end = $start + $per_page;
}
else
{
// error - show first set of results
$start = 0;
$end = $per_page;
}
}
else
{
// if page isn't set, show first set of results
$start = 0;
$end = $per_page;
}
// display pagination
// display data in table
echo "<div class='dancerbio'>";
echo "<div class='uts-1'>";
// loop through results of database query, displaying them in the table
for ($i = $start; $i < $end; $i++)
{
// make sure that PHP doesn't try to show results that don't exist
if ($i == $total_results) { break; }
// echo out the contents of each row into a table
$rowid = mysql_result($result, $i, 'id');
echo "<div class='uts-1-1'><a class='bodytxt5' href='webpagename-details.php?userid=$rowid'>" . mysql_result($result, $i, 'display_name') . "</a></div>";
}
// close table>
echo "<div class='ugen-1'></div>";
echo "</div>";
$prev = $_GET['page'] - 1;
echo "<div style='clear:both;height:1px;overflow: hidden;'></div>";
echo "<br /><a class='bodytxt5' href='webpagename.php?page=" . $prev . "'>Prev</a> ";
for ($i = 1; $i <= $total_pages; $i++)
{
echo "<a class='bodytxt5' href='webpagename.php?page=$i'>$i</a> ";
}
$next = $_GET['page'] + 1;
echo " <a class='bodytxt5' href='webpagename.php?page=" . $next . "'>Next</a> ";
echo "</div>";
// pagination
?>

Answer 1

replace this:
if (isset($_GET['page']) && is_numeric($_GET['page']))
{
$show_page = $_GET['page'];
// make sure the $show_page value is valid
if ($show_page > 0 && $show_page <= $total_pages)
{
$start = ($show_page -1) * $per_page;
$end = $start + $per_page;
}
else
{
// error - show first set of results
$start = 0;
$end = $per_page;
}
}
else
{
// if page isn't set, show first set of results
$start = 0;
$end = $per_page;
}
by this:
if (isset($_GET['page']) && is_numeric($_GET['page']))
{
$show_page = $_GET['page'];
if ($show_page > 0 && $show_page <= $total_pages)
{
$start = ($show_page -1) * $per_page;
$end = $start + $per_page;
}
elseif ($show_page > $total_pages)
{
$show_page=$total_pages;
$start = ($show_page -1) * $per_page;
$end = $start + $per_page;
}
else {
$show_page=1;
$start = 0;
$end = $per_page;
}
}
else {
$show_page=1;
$start = 0;
$end = $per_page;
}
then :
$prev=$show_page-1;
$next=$show_page+1;
if($show_page>1){//this way previsous won't appear if you are at page 1 already
//show previous div
}
if($show_page<$total_pages){ //this way next won't appear unless you are not at the last page
//show next div
}

Answer 2

Make a variable $page set it equal to $_GET['page'].
if(isset($_GET['page'])){
$page = $_GET['page'];
}
else{
$page = 1;
}
you need to put a condition before echoing previous link to check whether $_GET['page'] is set or not and is greater than 1.
Like this:
if($page!=($start+1)){
$prev = $page - 1;
echo "<div style='clear:both;height:1px;overflow: hidden;'></div>";
echo "<br /><a class='bodytxt5' href='webpagename.php?page=" . $prev . "'>Prev</a> ";
}
Add another condition for next
if($page!=$total_pages)
{
$next = $page+1
echo " <a class='bodytxt5' href='webpagename.php?page=" . $next . "'>Next</a> ";
echo "</div>";
}
I hope your issue is solved.
if (isset($_GET['page']) && is_numeric($_GET['page']))
{
$show_page = $_GET['page'];
// make sure the $show_page value is valid
if ($show_page > 0 && $show_page <= $total_pages)
{
$start = ($show_page -1) * $per_page;
$end = $start + $per_page;
}
else
{
// error - show first set of results
$start = 0;
$end = $per_page;
$show_page=1
}
}
else
{
// if page isn't set, show first set of results
$start = 0;
$end = $per_page;
$show_page=1;
}
// display pagination
// display data in table
echo "<div class='dancerbio'>";
echo "<div class='uts-1'>";
// loop through results of database query, displaying them in the table
for ($i = $start; $i < $end; $i++)
{
// make sure that PHP doesn't try to show results that don't exist
if ($i == $total_results) { break; }
// echo out the contents of each row into a table
$rowid = mysql_result($result, $i, 'id');
echo "<div class='uts-1-1'><a class='bodytxt5' href='webpagename-details.php?userid=$rowid'>" . mysql_result($result, $i, 'display_name') . "</a></div>";
}
// close table>
echo "<div class='ugen-1'></div>";
echo "</div>";
if($show_page!=($start+1)){
$prev = $page - 1;
echo "<div style='clear:both;height:1px;overflow: hidden;'></div>";
echo "<br /><a class='bodytxt5' href='webpagename.php?page=" . $prev . "'>Prev</a> ";
}
for ($i = 1; $i <= $total_pages; $i++)
{
echo "<a class='bodytxt5' href='webpagename.php?page=$i'>$i</a> ";
}
if($show_page!=$total_pages)
{
$next = $page+1
echo " <a class='bodytxt5' href='webpagename.php?page=" . $next . "'>Next</a> ";
echo "</div>";
}
// pagination
?>