Multiple Queries Compiling into one Loop

  • Hello,
    I’m trying to do something interesting but Google is not providing any answers. I thought maybe someone has done this before or perhaps could figure it out.

    I want to run multiple queries and compile them all into one loop. The reason is, I have tags that live in multiple custom taxonomies but are occasionally the same. I want my custom archive.php page to retrieve posts for all post types for the queried taxonomy term, no matter the taxonomies that it lives in.

    For instance, on our blog/database of authors’ homes, we have a News posts tagged “Edgar Allan Poe” and we have House Posts with the “author taxonomy” term “Edgar Allan Poe” for the Author sorting feature. In a couple places, I would like all posts with the term “Edgar Allan Poe” to be returned regardless of the taxonomy that holds it.

    I can envision a something like

    <?php
$posts = get_posts( array(
		'tag' => $tagslug,
		'post_type' => $post_types,
		'post_status' => 'publish',
 		));
$posts .= get_posts( array(
		'bookauthor' => $tagslug,
		'post_type' => $post_types,
		'post_status' => 'publish',
 		));
foreach($posts as $post) :
		setup_postdata($post);
?>

    but that is an invalid argument for foreach

    Any idea how one would compile the results of multiple queries, disregard duplicates, and return the results in a loop?

    Thanks!

Viewing 9 replies - 1 through 9 (of 9 total)
  • Thread Starter Taylor Baybutt

    (@taxbax)

    any ideas?

    The get_posts() function returns an array. Using .= in PHP appends one string to the end of another. The correct way to do this would be more like:

    <?php
$posts = get_posts( array( //first group of stuff ) );
$moreposts = get_posts( array( //second group of stuff ) );
$posts = array_merge( $posts, $moreposts );
foreach( $posts as $post ) :
    setup_postdata( $post );
    Thread Starter Taylor Baybutt

    (@taxbax)

    ohh right, I should have known…does array_merge disregard duplicates?

    Thanks!

    If the array items returned by get_posts() are numerically indexed (which I believe they are), duplicates will be included after you perform the array_merge(). The array_merge() function only overwrites items if they share the same non-numeric key.

    To get rid of duplicates, you could try using array_unique().

    Thread Starter Taylor Baybutt

    (@taxbax)

    this is proving very difficult.

    This is probably very inefficient but I have gotten pretty far with my limited php knowledge. my problem is that my $uniqueposts array is in an associative array which, it seems, the post__in query parameter will not accept. Here is my code, any help would be very much appreciated.

    <?php
$blogposts = get_posts(array(
		'tag' => $tagslug,
		'post_type' => $post_types,
		'post_status' => 'publish',
 		));
$authorposts = get_posts(array(
		'bookauthor' => $tagslug,
		'post_type' => $post_types,
		'post_status' => 'publish',
 		));
$mergedposts = array_merge( $blogposts, $authorposts );

$postids = array();
foreach( $mergedposts as $item ) {
$postids[]=$item->ID;
}
$uniqueposts = array_unique($postids);
print_r($uniqueposts);
$posts = get_posts(array(
		'post__in' => $uniqueposts,
 		));
 		foreach( $posts as $singlepost ) :
    setup_postdata( $post );?>

    I don’t understand why you’re trying to retrieve the posts twice. Why not just do something like the following (not tested, but I think it should work).

    <?php
$blogposts = get_posts(array(
		'tag' => $tagslug,
		'post_type' => $post_types,
		'post_status' => 'publish',
 		));
$authorposts = get_posts(array(
		'bookauthor' => $tagslug,
		'post_type' => $post_types,
		'post_status' => 'publish',
 		));
$mergedposts = array_unique( array_merge( $blogposts, $authorposts ) );
foreach( $mergedposts as $singlepost ) :
    setup_postdata( $post );?>

    Thread Starter Taylor Baybutt

    (@taxbax)

    I am trying to do this because you can only query one taxonomy at a time. I have a client that sometimes uses one and sometimes uses another, not ideal I know. So I want to return posts that have a given take no matter which taxonomy it is in.

    I had tried your solution but it returned a post with the id 0 that had no content.

    The way I was doing it was to retrieve an array of the unique post IDs and the I tried to query only posts with those IDs. Something went wrong but I am not sure what, it should have worked. Instead, two random posts got returned. I think two queries on the page (one in the sidebar) are conflicting.

    Thread Starter Taylor Baybutt

    (@taxbax)

    ahh, I’m dumb. I got got to put a post_type parameter in my post__in query. My final code is this:

    <?php
$term = get_term_by( 'slug', get_query_var( 'tag' ), "post_tag" );
$tagslug = $term->slug;
$post_types = get_post_types('','names');
?>
<?php
//first query
$blogposts = get_posts(array(
		'tag' => $tagslug, //first taxonomy
		'post_type' => $post_types,
		'post_status' => 'publish',
 		));
//second query
$authorposts = get_posts(array(
		'bookauthor' => $tagslug, //second taxonomy
		'post_type' => $post_types,
		'post_status' => 'publish',
 		));
$mergedposts = array_merge( $blogposts, $authorposts ); //combine queries

$postids = array();
foreach( $mergedposts as $item ) {
$postids[]=$item->ID; //create a new query only of the post ids
}
$uniqueposts = array_unique($postids); //remove duplicate post ids

$posts = get_posts(array(
		'post__in' => $uniqueposts, //new query of only the unique post ids on the merged queries from above
		'post_type' => $post_types,
		'post_status' => 'publish',
 		));
foreach( $posts as $post ) :
setup_postdata($post);
?>

    hope this helps someone else! If anyone can think of a more efficient way to do it, please share!

    Thanks a lot for sharing, you code was a great clue to solving some other problems which needed merging queries.
    Great work.

Viewing 9 replies - 1 through 9 (of 9 total)
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