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1. charismabiz
   Member
   Posted 12 months ago #

   Hi,

   I would like to retrieve posts from multiple categories (eg: all posts with category IDs 5 and 17). How would I do this?

2. MichaelH
   Moderator
   Posted 12 months ago #

   The Loop article in Codex has a Exclude posts from some Category that you could use with a few changes.

3. charismabiz
   Member
   Posted 11 months ago #

   I'm not using it within the loop... making a custom list on the side.

   Thanks for the help tho. I appreciate the effort :)

4. Otto42
   Moderator
   Posted 11 months ago #

   If you're retrieving posts, you're always making a Loop. Maybe not THE Loop, but it's a Loop nevertheless.

5. charismabiz
   Member
   Posted 11 months ago #

   Yep... but I thought "The Loop" was the main post retrieval loop?

   I've just rehecked the documentation at http://codex.wordpress.org/The_Loop

   The section provided by MichaelH is very useful, with a simple modification it would work as needed. However, the main question is how do I use this "the loop" for a sidebar module? Since "The Loop" deals only with posts/pages that will show up on that current page instead of ALL posts.

6. Otto42
   Moderator
   Posted 11 months ago #

   You just need a different kind of loop. This would be the best way to do it:

   <?php $my_query = new WP_Query('showposts=5&whatever=whatever');
   while ($my_query->have_posts()) : $my_query->the_post();
   ?>
   <!-- Do stuff... -->
   <?php endwhile; ?>

   Basically, it's a separate loop with some query parameters that you define directly.

7. charismabiz
   Member
   Posted 11 months ago #

   Mmmm, won't that be very inefficient tho, since I can only pass 1 category ID to WP_Query?

   eg: 6000 posts, 2000 that match one category, of which 400 match the second category. that would retrieve 2000 posts (can't retrieve less because say you want 5 posts. you won't know that the first Z will contain 5 that also match the second category condition), then have to go through it to get the X posts.

8. Otto42
   Moderator
   Posted 11 months ago #

   since I can only pass 1 category ID to WP_Query?

   Says who?

   ...new WP_Query('cat=5,17&showposts=5');

9. charismabiz
   Member
   Posted 11 months ago #

   Oh... ohhhh... wow, thanks buddy!

   Is there any documentation to WP_Query? The ones I found (http://codex.wordpress.org/Function_Reference/WP_Query and http://codex.wordpress.org/User:DavidHouse/Wordpress_Code_Flow) doesn't seem too helpful.

   Specifically, does that display posts that match BOTH category 5 and 17, or is it "5 or 17"?

   Also, how do I get the category ID that it is in, when in the loop?

   Thanks again!

10. Otto42
    Moderator
    Posted 11 months ago #

    The WP_Query constructor takes the same arguments as query_posts() does.

    And I think it gets any posts in "either 5 or 17", actually. There does not appear to be any way to make it get posts in "both 5 and 17".

    To get category information for a post in the loop, use get_the_category().

11. malheiro
    Member
    Posted 11 months ago #

    hey charismabiz,

    i had the same need as you and i managed to show only posts that were under two categories. i adapted the code from the following:

    http://codex.wordpress.org/Template_Tags/query_posts#Excluding_Multiple_Categories

    it's kinda dumb solution: i first queried one category with query_posts() and then narrowed to the posts that also were under the second category with the conditional in_category() placed inside the loop.

    doing this way, wp will only show the overlapping subgroup of posts that are under both categories :)

12. themos
    Member
    Posted 9 months ago #

    since I can only pass 1 category ID to WP_Query?
    Says who?
    ...new WP_Query('cat=5,17&showposts=5');

    This was exactly what i needed, thank you!!

13. WordpressChina
    Member
    Posted 9 months ago #

    One more thing... I have asked this on other threads without a response over last few months and so I hope this is topical here:

    Now that I can retrieve posts from multiple categories, how do I limit it to only posts from the last X days? for example I want the last 7 days... any ideas?

14. WordpressChina
    Member
    Posted 9 months ago #

    Any idea how I can retrieve posts from multiple categories, but only limit them to posts from the last X days?

15. WordpressChina
    Member
    Posted 9 months ago #

    Sorry, but any idea how I can retrieve posts from multiple categories, but only limit them to posts from the last X days?

    I can't find codex info and I'm sure this is a need for others!

16. iblastoff
    Member
    Posted 8 months ago #

    why is this place using such a poorly laid out forum? 90% of posts i've looked up in order to find an answer come to conclusions exactly like this thread. completely unanswered.

17. WordpressChina
    Member
    Posted 8 months ago #

    Yes, it would be good if I could figure out how to get X days.

    Posts on this forum seem to disappear from view after a while, so only a good Google search brings back old posts and unanswered queries from long ago... :(

18. jeremyduffy
    Member
    Posted 1 month ago #

    Ok, I finally figured out how to do multiple categories. Just pre-load your $posts var by using

    query_posts(array('category__and'=>array(3,4,8)))

    Where 3, 4, and 8 are the categories you want. Then call the loop like normal and magic.

    Anyway, I have a whole write-up on it with code that shows how to make the categories multi-selectable and such here:

    http://www.jeremyduffy.com/computers-internet/wordpress-stuff/wordpress-multiple-categories/

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