[WordPress] Paging on Index Page Not Working With posts_per_page

Question

I'm working on a theme that has both a project page and a blog. I want to keep the blog posts at the default of 10, so I used the posts_per_page option to limit the number of projects on the first page, like this:

<?php $catID = get_cat_id('Projects');
$number = get_option('grd_portfolio_number');
if(have_posts()) : 
$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
query_posts('paged=' . $paged . '&posts_per_page=' . $number . '&cat=' . $catID); ?>
<?php while(have_posts()) : the_post(); ?>

So if I set it to 4 (from the Theme Options page, not settings), it limits the first page to 4 projects, but the second page doesn't show anything, but if I go to my WP settings and replace that 10 to a 4, it will display the rest of my content properly.

I'm guessing that the setting is overriding something, but I can't figure out how to fix it.

Answer 1

If you just want to change the posts per page and keep all other parameters as before (like category, pagenumber, year in archive etc.) just add only the posts_per_page to the query string:

// put this at the top of your function
global $query_string;
..
// append the posts_per_page parameter to the other parameters
query_posts($query_string.'&posts_per_page=' . $number . ');