How to Explode and combine values in a wordpress query

Question

I have a multiple pages in wordpress all with a single custom field called portfolio-section.

some examples of the data are

page 1 : portfolio-section = red
page 2 : portfolio-section = blue
page 3 : portfolio-section = red
page 4 : portfolio-section = red,blue

now im executing a wp query:

$querystr = "
    SELECT wposts.*
    FROM $wpdb->posts wposts, $wpdb->postmeta wpostmeta
    WHERE wposts.ID = wpostmeta.post_id
    AND wpostmeta.meta_key = 'portfolio-section'
    AND wposts.post_status = 'publish'
    ORDER BY wpostmeta.meta_value DESC
 ";
$pageposts = $wpdb->get_results($querystr, OBJECT);
 foreach ($pageposts as $post) {

 echo '<li><a rel="all '.get_post_meta($post->ID, 'portfolio-section', $single = true).'"><span>'.get_post_meta($post->ID, 'portfolio-section', $single = true).'</span></a></li>';

 }

which returns the values : "red", "blue", "red,blue"

however what i want to do is explode the "red,blue" and somehow combine it so the final list is

"red", "blue"

Answer 1

I'm not exactly sure what you're attempting to achieve but if you need to use explode to separate the "red,blue" it would be:

$colors = explode(',',$row);