Second page of pagination displays all results - php

Question

I have spent days on this and can't make any progress, any help will be really appreciated. I have a page that processes a query from a form and displays the results. The first page of results works as expected showing number of rows found and displaying some of the results but when I click to the next page I just get all the results in the database, like the query has been forgotten.
<?php include_once "db_conx.php";
if (isset($_GET['submit']) && $_GET['submit'] == 'submit_1'){
//Build Search Query from form data
$whereClauses = array();
if (! empty($_GET['location'])) $whereClauses[] ="(location ='".mysqli_real_escape_string($db_conx,$_GET['location'])."' OR location_2 ='".mysqli_real_escape_string($db_conx,$_GET['location'])."' OR location_3 ='".mysqli_real_escape_string($db_conx,$_GET['location'])."' OR location_4 ='".mysqli_real_escape_string($db_conx,$_GET['location'])."')";
if (! empty($_GET['jobtitle'])) $whereClauses[] ="(jobtitle LIKE '%".mysqli_real_escape_string($db_conx,$_GET['jobtitle'])."')";
if (!empty($_GET['start']))
if ($_GET['start'] == "today") {
$whereClauses[] = "START = CURDATE()";
}
else if ($_GET['start'] == "tomorrow") {
$whereClauses[] = "START = DATE_ADD( CURDATE( ) , INTERVAL( 9 - IF( DAYOFWEEK( CURDATE( ) ) =1, 8, DAYOFWEEK( CURDATE( ) ) ) ) DAY )";
}
else if ($_GET['start'] == "next_week") {
$whereClauses[] = "START = DATE_ADD( CURDATE( ) , INTERVAL( 9 - IF( DAYOFWEEK( CURDATE( ) ) =1, 8, DAYOFWEEK( CURDATE( ) ) ) )
DAY )";
}
else if ($_GET['start'] == "this_month") {
$whereClauses[] = "START BETWEEN DATE_SUB( CURDATE( ) , INTERVAL( DAY( CURDATE( ) ) -1 ) DAY ) AND LAST_DAY( NOW( ) )";
}
else if ($_GET['start'] == "next_month") {
$whereClauses[] = "start BETWEEN DATE_SUB(LAST_DAY(DATE_ADD(NOW(), INTERVAL 1 MONTH)),INTERVAL DAY(LAST_DAY(DATE_ADD(NOW(), INTERVAL 1 MONTH)))-1 DAY) AND LAST_DAY(DATE_ADD(NOW(), INTERVAL 1 MONTH))";
}
else if ($_GET['start'] == "in_future") {
$whereClauses[] = "START > CURDATE()";
}
$where = '';
if (count($whereClauses) > 0) {
$where = ' WHERE '.implode(' AND ',$whereClauses);
}
// The first query to count the number of rows
$sql = "SELECT COUNT(id) FROM users " .$where."";
$query = mysqli_query($db_conx, $sql);
$row = mysqli_fetch_row($query);
// Here we have the total row count
$rows = $row[0];
// The number of results to display per page
$page_rows = 5;
// This tells us the page number of our last page
$last = ceil($rows/$page_rows);
// This makes sure $last cannot be less than 1
if($last < 1){
$last = 1;
}
// Establish the $pagenum variable
$pagenum = 1;
// Get pagenum from URL vars if it is present, else it is = 1
if(isset($_GET['pn'])){
$pagenum = preg_replace('#[^0-9]#', '', $_GET['pn']);
}
// Make sure the page number isn't below 1, or more than our $last page
if ($pagenum < 1) {
$pagenum = 1;
} else if ($pagenum > $last) {
$pagenum = $last;
}
// This sets the range of rows to query for the chosen $pagenum
$limit = 'LIMIT ' .($pagenum - 1) * $page_rows .',' .$page_rows;
// The Query again to get just one page worth of rows by applying $limit
$sql="SELECT * FROM users " .$where." ORDER BY notescheck DESC $limit";
$query = mysqli_query($db_conx, $sql);
// This shows the user what page they are on, and the total number of pages
$textline1 = "Results (<b>$rows</b>)";
$textline2 = "Page <b>$pagenum</b> of <b>$last</b>";
// Establish the $paginationCtrls variable
$paginationCtrls = '';
// If there is more than 1 page worth of results
if($last != 1){
/* First we check if we are on page one. If we are then we don't need a link to
the previous page or the first page so we do nothing. If we aren't then we
generate links to the first page, and to the previous page. */
if ($pagenum > 1) {
$previous = $pagenum - 1;
$paginationCtrls .= '<ul class="pagination"><li>Previous</li></ul> ';// Render clickable number links that should appear on the left of the target page number
for($i = $pagenum-4; $i < $pagenum; $i++){
if($i > 0){
$paginationCtrls .= '<ul class="pagination"><li>'.$i.'</li>
</ul> ';
}
}
}
// Render the target page number, but without it being a link
// Render clickable number links that should appear on the right of the target page number
for($i = $pagenum+1; $i <= $last; $i++){
$paginationCtrls .= '<ul class="pagination"><li>'.$i.'</li>
</ul> ';
if($i >= $pagenum+4){
break;
}
}
// This does the same as above, only checking if we are on the last page, and then generating the "Next"
if ($pagenum != $last) {
$next = $pagenum + 1;
$paginationCtrls .= '<ul class="pagination"><li>Next</li>
</ul> ';
}
}
}
$list = '';
while($row = mysqli_fetch_array($query, MYSQLI_ASSOC)){
$id = $row["id"];
$firstname = $row["firstname"];
$lastname = $row["lastname"];
$list .= '<p>'.$firstname.' '.$lastname.' Profile - Click the link to view user<br></p>';
}
// Close your database connection
mysqli_close($db_conx);
?>

Answer 1

$_SERVER['PHP_SELF'] refers to the script, but not the full url. This means that you loose all the information you previously had in your query string. Actually, the only reason this works, is because your script name is the same as the url. PHP_SELF is actually for internal use (including files) and not intended for building urls at all.
You can solve this by storing the values in cookies, or by using the full url (including query string) when you build the links for previous and next pages.
When building the url, you can use $_SERVER['REQUEST_URI']. This gives you the relative url to your script, similar to $_SERVER['PHP_SELF'], but actually giving the document part of the request url.
Additionally, you can use $_SERVER['QUERY_STRING'] to get the entire query string of the request, or you can use $_GET[] to get each of the query string values and only copy those that you want to use in the url.
To simply copy everything that is in the url, and just change the page number, you can do this:
$pagenum = 5; // example.
$urlParams = $_GET; // Copy the entiry query string.
$urlParams['pn'] = $pagenum - 1; // Replace the page number.
$previous = http_build_query($urlParams); // Build a new query string.
$urlParams['pn'] = $pagenum + 1;
$next = http_build_query($urlParams);
And then you can build a link like this:
'Previous page
Next page'