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query_posts function in wordpress

reference: http://codex.wordpress.org/Function_Reference/query_posts

Description

query_posts() can be used to control which posts show up in The Loop. It accepts a variety of parameters in the same format as used in your URL (e.g. p=4 to show only post of ID number 4).

Why go through all the trouble of changing the query that was meticulously created from your given URL? You can customize the presentation of your blog entries by combining it with page logic (like the Conditional Tags) — all without changing any of the URLs.

Common uses might be to:

  • Display only a single post on your homepage (a single Page can be done via Settings -> Reading).
  • Show all posts from a particular time period.
  • Show the latest post (only) on the front page.
  • Change how posts are ordered.
  • Show posts from only one category.
  • Exclude one or more categories.

Important note

The query_posts function is intended to be used to modify the main page Loop only. It is not intended as a means to create secondary Loops on the page. If you want to create separate Loops outside of the main one, you should use get_posts() instead. Use of query_posts on Loops other than the main one can result in your main Loop becoming incorrect and possibly displaying things that you were not expecting.

The query_posts function overrides and replaces the main query for the page. To save your sanity, do not use it for any other purpose.

Usage

<?php

//The Query
query_posts('posts_per_page=5');

//The Loop
if ( have_posts() ) : while ( have_posts() ) : the_post();
 ..
endwhile; else:
 ..
endif;

//Reset Query
wp_reset_query();

?>

Usage Note

Place a call to query_posts() in one of your Template files before The Loop begins. The wp_query object will generate a new SQL query using your parameters. When you do this, WordPress ignores the other parameters it receives via the URL (such as page number or category). If you want to preserve that information, you can use the $query_string global variable in the call to query_posts().

For example, to set the display order of the posts without affecting the rest of the query string, you could place the following before The Loop:

global $query_string;
query_posts($query_string . "&order=ASC");

When using query_posts in this way, the quoted portion of the argument must begin with an ampersand (&).

Parameters

This is not an exhaustive list yet. It is meant to show some of the more common things possible with setting your own queries.

Category Parameters

Show posts only belonging to certain categories.

  • cat – must use cat ids
  • category_name
  • category__and – must use cat ids
  • category__in – must use cat ids
  • category__not_in – must use cat ids

Show One Category by ID

Display posts from only one category ID (and any children of that category):

query_posts('cat=4');

Show One Category by Name

Display posts from only one category by name:

query_posts('category_name=Staff Home');

Show Several Categories by ID

Display posts from several specific category IDs:

query_posts('cat=2,6,17,38');

Exclude Posts Belonging to Only One Category

Show all posts except those from a category by prefixing its ID with a ‘-’ (minus) sign.

query_posts('cat=-3');

This excludes any post that belongs to category 3.

Multiple Category Handling

Display posts that are in multiple categories. This shows posts that are in both categories 2 and 6:

query_posts(array('category__and' => array(2,6)));

To display posts from either category 2 OR 6, you could use cat as mentioned above, or by using category__in (note this does not show posts from any children of these categories):

query_posts(array('category__in' => array(2,6)));

You can also exclude multiple categories this way:

query_posts(array('category__not_in' => array(2,6)));

Tag Parameters

Show posts associated with certain tags.

  • tag
  • tag_id – must use tag ids
  • tag__and – must use tag ids
  • tag__in – must use tag ids
  • tag__not_in – must use tag ids
  • tag_slug__and
  • tag_slug__in

Fetch posts for one tag

query_posts('tag=cooking');

This must use the tag slugs. E.g. query_posts(‘tag=dinner-recipe’); for the tag “dinner recipe”

Fetch posts that have either of these tags

query_posts('tag=bread,baking');

Fetch posts that have all three of these tags:

query_posts('tag=bread+baking+recipe');

Multiple Tag Handling

Display posts that are tagged with both tag id 37 and tag id 47:

query_posts(array('tag__and' => array(37,47)));

To display posts from either tag id 37 or 47, you could use tag as mentioned above, or explicitly specify by using tag__in:

query_posts(array('tag__in' => array(37,47)));

Display posts that do not have any of the two tag ids 37 and 47:

query_posts(array('tag__not_in' => array(37,47)));

The tag_slug__in and tag_slug__and behave much the same, except match against the tag’s slug.

Also see Ryan’s discussion of Tag intersections and unions.

Author Parameters

You can also restrict the posts by author.

  • author=3
  • author=-3 – exclude author id 3 posts
  • author_name=Harriet

Note: author_name operates on the user_nicename field, whilst author operates on the author id field.

Display all Pages for author=1, in title order, with no sticky posts tacked to the top:

query_posts('caller_get_posts=1&author=1&post_type=page&post_status=publish&orderby=title&order=ASC');

Post & Page Parameters

Retrieve a single post or page.

  • 'p' => 27 – use the post ID to show that post
  • 'name' => 'about-my-life' – query for a particular post that has this Post Slug
  • 'page_id' => 7 – query for just Page ID 7
  • 'pagename' => 'about' – note that this is not the page’s title, but the page’s path
  • 'posts_per_page' => 1 – use 'posts_per_page' => 3 to show 3 posts. Use 'posts_per_page' => -1 to show all posts
  • 'showposts' => 1 – use 'showposts' => 3 to show 3 posts. Use 'showposts' => -1 to show all posts. Deprecated in favor of posts_per_page
  • 'post__in' => array(5,12,2,14,7) – inclusion, lets you specify the post IDs to retrieve
  • 'post__not_in' => array(6,2,8) – exclusion, lets you specify the post IDs NOT to retrieve
  • 'post_type' => 'page' – returns Pages; defaults to value of post; can be any, attachment, page, post, or revision. any retrieves any type except revisions. Also can designate custom post types (e.g. movies).
  • 'post_status' => 'publish' – returns publish works. Also could use pending, draft, future, private, trash. For inherit see get_children. Status of trash added with Version 2.9.
  • 'post_parent' => 93 – return just the child Pages of Page 93.

To return both posts and custom post type movie

query_posts( array( 'post_type' => array('post', 'movie') ) );

Sticky Post Parameters

Sticky posts first became available with WordPress Version 2.7. Posts that are set as Sticky will be displayed before other posts in a query, unless excluded with the caller_get_posts=1 parameter.

  • array('post__in'=>get_option('sticky_posts')) – returns array of all sticky posts
  • caller_get_posts=1 – To exclude sticky posts being included at the beginning of posts returned, but the sticky post will still be returned in the natural order of that list of posts returned.

To return just the first sticky post:

$sticky=get_option('sticky_posts') ; 
query_posts('p=' . $sticky[0]);

or

$args = array(
	'posts_per_page' => 1,
	'post__in'  => get_option('sticky_posts'),
	'caller_get_posts' => 1
);
query_posts($args);

Note: the second method returns only the more recent sticky post; if there are not sticky posts, it returns the last post published.

To return just the first sticky post or nothing:

$sticky = get_option('sticky_posts');
$args = array(
	'posts_per_page' => 1,
	'post__in'  => $sticky,
	'caller_get_posts' => 1
);
query_posts($args);
if($sticky[0]) {
   // insert here your stuff...
}

To exclude all sticky posts from the query:

query_posts(array("post__not_in" =>get_option("sticky_posts")));

Return ALL posts with the category, but don’t show sticky posts at the top. The ‘sticky posts’ will still show in their natural position (e.g. by date):

query_posts('caller_get_posts=1&posts_per_page=3&cat=6'); 

Return posts with the category, but exclude sticky posts completely, and adhere to paging rules:

<?php
$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
$sticky=get_option('sticky_posts');
$args=array(
   'cat'=>3,
   'caller_get_posts'=>1,
   'post__not_in' => $sticky,
   'paged'=>$paged,
   );
query_posts($args);
?>

Time Parameters

Retrieve posts belonging to a certain time period.

  • hour= – hour (from 0 to 23)
  • minute= – minute (from 0 to 60)
  • second= – second (0 to 60)
  • day= – day of the month (from 1 to 31)
  • monthnum= – month number (from 1 to 12)
  • year= – 4 digit year (e.g. 2009)
  • w= – week of the year (from 0 to 53) and uses the MySQL WEEK command Mode=1.

Returns posts for just the current date:

$today = getdate();
query_posts('year=' .$today["year"] .'&monthnum=' .$today["mon"] .'&day=' .$today["mday"] );

Returns posts for just the current week:

$week = date('W');
$year = date('Y');
query_posts('year=' . $year .'&w=' .$week );

Returns posts dated December 20:

query_posts( 'monthnum=12&day=20' );

Note: The queries above return posts for a specific date period in history, i.e. “Posts from X year, X month, X day”. They are unable to fetch posts from a timespan relative to the present, so queries like “Posts from the last 30 days” or “Posts from the last year” are not possible with a basic query, and require use of the posts_where filter to be completed. The examples below use the posts_where filter, and should be modifyable for most time-relative queries.

Return posts for posts for March 1 to March 15, 2009:

<?php
//Create a new filtering function that will add our where clause to the query
function filter_where($where = '') {
  //posts for March 1 to March 15, 2009
  $where .= " AND post_date >= '2009-03-01' AND post_date < '2009-03-16'";
  return $where;
}
// Register the filtering function
add_filter('posts_where', 'filter_where');
// Perform the query, the filter will be applied automatically
query_posts($query_string);
?>

Return posts from the last 30 days:

<?php
//Create a new filtering function that will add our where clause to the query
function filter_where($where = '') {
  //posts in the last 30 days
  $where .= " AND post_date > '" . date('Y-m-d', strtotime('-30 days')) . "'";
  return $where;
}
// Register the filtering function
add_filter('posts_where', 'filter_where');
// Perform the query, the filter will be applied automatically
query_posts($query_string);
?>

Return posts 30 to 60 days old

<?php
//Create a new filtering function that will add our where clause to the query
function filter_where($where = '') {
  //posts  30 to 60 days old
  $where .= " AND post_date >= '" . date('Y-m-d', strtotime('-60 days')) . "'" . " AND post_date <= '" . date('Y-m-d', strtotime('-30 days')) . "'";
  return $where;
}
// Register the filtering function
add_filter('posts_where', 'filter_where');
// Perform the query, the filter will be applied automatically
query_posts($query_string);
?>

Pagination Parameters

  • nopaging=true – will disable pagination, displaying all posts
  • posts_per_page=10 – number of posts to show per page
  • paged=2 – show the posts that would normally show up just on page 2 when using the “Older Entries” link. You should set this to get_query_var( 'paged' ) if you want your query to work with pagination.
  • order=ASC – show posts in chronological order, DESC to show in reverse order (the default)

Offset Parameter

You can displace or pass over one or more initial posts which would normally be collected by your query through the use of the offset parameter.

The following will display the 5 posts which follow the most recent (1):

query_posts('posts_per_page=5&offset=1');

Orderby Parameters

Sort retrieved posts by this field.

  • orderby=author
  • orderby=date
  • orderby=title
  • orderby=modified
  • orderby=menu_order used most often for Pages (Order field in the Edit Page ➝ Attributes box) and attachments (the integer fields in the Insert / Upload Media ➝ Gallery dialog), but could be used for any post type with distinct menu_order values (they all default to 0).
  • orderby=parent
  • orderby=ID
  • orderby=rand
  • orderby=meta_value Note: A meta_key=keyname must also be present in the query.
  • orderby=meta_value_num – Order by numeric meta value (available with Version 2.8)
  • orderby=none – No order (available with Version 2.8)
  • orderby=comment_count – (available with Version 2.9)

Order Parameters

Designates the ascending or descending order of the ORDERBY parameter.

  • order=ASC – ascending from lowest to highest values (1, 2, 3; a, b, c)
  • order=DESC – descending from highest to lowest values (3, 2, 1; c, b, a)

Custom Field Parameters

Retrieve posts (or Pages) based on a custom field key or value.

  • meta_key=
  • meta_value=
  • meta_compare= – operator to test the meta_value=, default is ‘=’, with other possible values of ‘!=’, ‘>’, ‘>=’, ‘<’, or ‘<=’

Returns posts with custom fields matching both a key of ‘color’ AND a value of ‘blue’:

query_posts('meta_key=color&meta_value=blue'); 

Returns posts with a custom field key of ‘color’, regardless of the custom field value:

query_posts('meta_key=color'); 

Returns posts where the custom field value is ‘color’, regardless of the custom field key:

query_posts('meta_value=color');

Returns any Page where the custom field value is ‘green’, regardless of the custom field key:

query_posts('post_type=page&meta_value=green');

Returns both posts and Pages with a custom field key of ‘color’ where the custom field value IS NOT EQUAL TO ‘blue’:

query_posts('post_type=any&meta_key=color&meta_compare=!=&meta_value=blue');

Returns posts with custom field key of ‘miles’ with a custom field value that is LESS THAN OR EQUAL TO 22. Note the value 99 will be considered greater than 100 as the data is stored as strings, not numbers.

query_posts('meta_key=miles&meta_compare=<=&meta_value=22');

Combining Parameters

You may have noticed from some of the examples above that you combine parameters with an ampersand (&), like so:

query_posts('cat=3&year=2004');

Posts for category 13, for the current month on the main page:

if (is_home()) {
query_posts($query_string . '&cat=13&monthnum=' . date('n',current_time('timestamp')));
}

At 2.3 this combination will return posts belong to both Category 1 AND 3, showing just two (2) posts, in descending order by the title:

 query_posts(array('category__and'=>array(1,3),'posts_per_page'=>2,'orderby'=>title,'order'=>DESC));

In 2.3 and 2.5 one would expect the following to return all posts that belong to category 1 and is tagged “apples”

query_posts('cat=1&tag=apples');

A bug prevents this from happening. See Ticket #5433. A workaround is to search for several tags using +

query_posts('cat=1&tag=apples+apples');

This will yield the expected results of the previous query. Note that using ‘cat=1&tag=apples+oranges’ yields expected results.

Examples

Exclude Categories From Your Home Page

Placing this code in your index.php file will cause your home page to display posts from all categories except category ID 3.

<?php
   if (is_home()) {
      query_posts("cat=-3");
   }
?>

You can also add some more categories to the exclude-list (tested with WP 2.1.2):

<?php
   if (is_home()) {
      query_posts("cat=-1,-2,-3");
   }
?>

Retrieve a Particular Post

To retrieve a particular post, you could use the following:

<?php
// retrieve one post with an ID of 5
query_posts('p=5');      
?>

If you want to use the Read More functionality with this query, you will need to set the global $more variable to 0.

<?php
// retrieve one post with an ID of 5
query_posts('p=5');
      
global $more;
// set $more to 0 in order to only get the first part of the post
$more = 0; 

// the Loop
while (have_posts()) : the_post(); 
  // the content of the post
  the_content('Read the full post »'); 
endwhile;
?>

Retrieve a Particular Page

To retrieve a particular page, you could use the following:

<?php
query_posts('page_id=7');      //retrieves page 7 only
?>

or

<?php
query_posts('pagename=about'); //retrieves the about page only
?>

For child pages, the slug of the parent and the child is required, separated by a slash. For example:

<?php
query_posts('pagename=parent/child'); // retrieve the child page of a parent
?>

Passing variables to query_posts

You can pass a variable to the query with two methods, depending on your needs. As with other examples, place these above your Loop:

Example 1

In this example, we concatenate the query before running it. First assign the variable, then concatenate and then run it. Here we’re pulling in a category variable from elsewhere.

 <?php
 $categoryvariable=$cat; // assign the variable as current category
 $query= 'cat=' . $categoryvariable. '&orderby=date&order=ASC'; // concatenate the query
 query_posts($query); // run the query
 ?>

Example 2

In this next example, the double quotes tell PHP to treat the enclosed as an expression. For this example, we are getting the current month and the current year, and telling query_posts to bring us the posts for the current month/year, and in this case, listing in ascending order so we get the oldest post at the top of the page.

<?php
$current_month = date('m');
$current_year = date('Y');

query_posts("cat=22&year=$current_year&monthnum=$current_month&order=ASC");
?>
<!-- put your loop here -->

Example 3

This example explains how to generate a complete list of posts, dealing with pagination. We can use the default $query_string telling query_posts to bring us a full posts listing. We can also modify the posts_per_page query argument from -1 to the number of posts you want to show on each page; in this last case, you’ll probably want to use posts_nav_link() to navigate the generated archive.

<?php 
query_posts($query_string.'&posts_per_page=-1');
while(have_posts()) { the_post();
<!-- put your loop here -->
}
?>

Example 4

If you don’t need to use the $query_string variable, another method exists that is more clear and readable, in some more complex cases. This method puts the parameters into an array. The same query as in Example 2 above could be done like this:

query_posts(array(
 'cat'      => 22, 
 'year'     => $current_year, 
 'monthnum' => $current_month, 
 'order'    => 'ASC',
));

As you can see, with this approach, every variable can be put on its own line, for easier reading.

Preserving the Original Query (Pagination etc.)

By default running query_posts will completely overwrite all existing query variables on the current page. Pagination, categories dates etc. will be lost and only the variables you pass into query_posts will be used.

If you want to preserve the original query you can merge the original query array into your parameter array:

global $wp_query;
query_posts(
	array_merge(
		array('cat' => 1),
		$wp_query->query
	)
);

Usage Tips

The “Blog pages show at most” parameter in Settings > Reading can influence your results. To overcome this, add the ‘posts_per_page’ parameter. For example:

query_posts('category_name=The Category Name&posts_per_page=-1');  //returns ALL from the category