I have an action setup on pre_get_posts which I would like to use post__in on.

I used the following code as a test:

$query->set('post__not_in', array(74485,1528,71460));

This works, the total number of posts is reduced by those 3. However, what if I want to use post__in to just return those 3 posts? I tried:

$query->set('post__in', array(74485,1528,71460));

But that didn't work. I thought maybe it was because post__not_in is already being used (as the codex says post__in and post__not_in can't be used together. So I tried:

$query->set('post__not_in', '');
$query->set('post__in', array(74485,1528,71460));

But this still doesn't work.

Any help please? Thanks

  • I don't understand your actual question here. Are you trying to run two instances of pre_get_posts on the same query. If so, why? What are you trying to do Jul 30, 2014 at 12:09
  • I'm trying to filter the results of a query using pre_get_posts. Currently lots of results are returned, I'd like to only include those 3 post IDs (just for testing purposes, I have a much larger array of post IDS I'd like returned). At the moment I can exclude post IDs with post__not_in (this also works with the large array of IDS I have) but I can't include only them. I suppose another way would be to get an array of all post ids and compare that to the array I have?
    – patrickzdb
    Jul 30, 2014 at 12:11
  • Are you using sticky posts Jul 30, 2014 at 12:14
  • I'm not sure, how would I check? This is a woocommerce product loop, so post_type=product
    – patrickzdb
    Jul 30, 2014 at 12:15
  • I tried adding $query->set('ignore_sticky_posts', 1); but still no joy.
    – patrickzdb
    Jul 30, 2014 at 12:27

1 Answer 1


I just ran into this with WooCommerce. I ended up passing the IDs I needed to a variable for safe keeping, and then hooking a function with extremely low priority. That worked fine. I figure woocommerce or what of my cleint's 8000000 plugins was overwriting post__in.

add_filter('pre_get_posts', 'assign_ids', 1000);
  • Cheers, that's a nice method. I ended up using a different solution in the end. Could I see your code for assign_ids?
    – patrickzdb
    Aug 20, 2014 at 8:50
  • MILION THANKS! the low priority solved my hugeeee problems!
    – T.Todua
    Jun 18, 2015 at 22:26

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