Pagination issue in PHP - php

Question

I have a simple pagination script for my search, but I'm facing some trouble.
When I change the page, the query returns to the initial definition.
Something like:
Definition: Select * from a;
Search: Select * from a where a.id = 1;
And then when I go to the 2nd page the query becames that: Select * from a; again.
The code: I have a form with some fields for the search and then the script:
$sqlCount_pre = "SELECT COUNT('*') FROM a ";
$sqlCount_pre .= " INNER JOIN b ON a.id = b.id ";
if( sizeof( $where ) ){
$sqlCount_pre .= ' WHERE '.implode( ' AND ',$where );
}
$max = 2;
$sqlCount = mysql_query($sqlCount_pre);
$sqlResult = ceil(mysql_result($sqlCount, 0) / $max);
$pg = (isset($_GET["pg"])) ? (int)$_GET["pg"] : 1 ;
$start = ($pg - 1) * $max;
$sqlQuery = "SELECT a.* FROM a ";
$sqlQuery .= " INNER JOIN b ON a.id = b.id ";
if( sizeof( $where ) ){
$sqlQuery .= ' WHERE '.implode( ' AND ',$where );
$sqlQuery .= " LIMIT $start, $max";
}else{
$sqlQuery .= " LIMIT $start, $max";
}
$sql = mysql_query($sqlQuery) or die(mysql_error());
Then i show the result in the page.
After that i put the page links, as in this code:
<?php
if($sqlResult > 1 && $pg<= $sqlResult){
for($i=1; $i<=$sqlResult; $i++){
echo "<a href='?pg=$i'>$i</a> ";
}
}
?>
Is there something wrong or missing in this code?

Answer 1

When you combine a search form with pagination, you need to embed the search parameters in the paging links.
<?php
if($sqlResult > 1 && $pg<= $sqlResult){
$query = $_GET;
for($i=1; $i<=$sqlResult; $i++){
$query['pg'] = $i;
echo "<a href='?" . http_build_query($query) ."'>$i</a> ";
}
}
?>
The above code takes everything in your current query string and adds in the applicable pg attribute when building the pagination links.
-- edit --
Combining a POST search form with pagination gets a little weird. There are a couple things you can do:
Use javascript to populate a hidden "page" field in the form when you click one of the pagination links, and resubmit the form, e.g.:
$('.pagination-link').on('click', function() {
$('#page').val($(this).html()); //where you have a hidden field #page
$('$searchform').submit();
});
OR
Change the form method to GET, and use the example I posted above

Answer 2

is_int() doc is here
$pg = (isset($_GET["pg"]) && is_int($_GET["pg"])) ? (int)$_GET["pg"] : 1 ;
of course with this there is no reason for (int)... because we've already established $_GET["pg"] as an int, so type conversion is moot.
$pg = (isset($_GET["pg"]) && is_int($_GET["pg"]) && $_GET["pg"] > 0) ? $_GET["pg"] : 1 ;
this will return 1 if
$_GET["pg"]
returns a string of numbers like "42". For an alternative and is_numeric and a description and comparison of the two check out this article.
If GET returns a string
pg_escape_string($_GET["pg"])
pg_escape_string doc
Back to your original question. When you change pages the limit is not being executed. So the offset and max are not being set. take a look at the query executed when you hit the second page. Are you calculating the offset correctly?
are you only specifying $pg in
echo "<a href='?pg=$i'>$i</a> ";
you'd have to put in the search term as well to pass it to the $where array. The count will be 0 if you don't and that's why the implode doesn't happen.
multiple variables here