Template Tags/query posts

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Содержание 1 Description 2 Important note 3 Usage 4 Examples 4.1 Exclude Categories From Your Home Page 4.2 Retrieve a Particular Post 4.3 Retrieve a Particular Page 4.4 Passing variables to query_posts 4.4.1 Example 1 4.4.2 Example 2 4.4.3 Example 3 4.4.4 Example 4 5 Parameters 5.1 Category Parameters 5.2 Tag Parameters 5.3 Author Parameters 5.4 Post & Page Parameters 5.5 Time Parameters 5.6 Page Parameters 5.7 Offset Parameter 5.8 Orderby Parameters 5.9 Custom field Parameters 5.10 Combining Parameters

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 create separate WP_Query objects and use those 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

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 variable $query_string 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:

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

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

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 so we get oldest post at top of page.

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

<?php 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, then another method exists that is more clear and readable, in some more complex cases. This method puts the parameters into an array, and then passes the 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 simpler reading.

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
• category_name
• category__and
• category__in
• category__not_in

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

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

This only shows posts that are in both categories 2 and 6. To display posts from either category 2 OR 6, you could use cat as mentioned above, or explicitly specify by using category__in:

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__and
• tag__in
• tag_slug__and
• tag_slug__in

Fetch posts for one tag

query_posts('tag=cooking');

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 in multiple tags:

query_posts(array('tag__and' => array('bread','baking'));

This only shows posts that are in both tags 'bread' and 'baking'. To display posts from either tag, you could use tag as mentioned above, or explicitly specify by using tag__in:

query_posts(array('tag__in' => array('bread','baking'));

The tag_slug__in and tag_slug__and behave much the same, except match against the tag's slug instead of the tag itself.

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

Author Parameters

You can also restrict the posts by author.

• author_name=Harriet
• author=3

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

Post & Page Parameters

Retrieve a single post or page.

• p=1 - use the post ID to show the first post
• name=first-post - use the Post Slug to show the first post
• page_id=7
• pagename=about - note that this is not the page's title, but the page's path
• showposts=1 (you can also use showposts=3, or any number to display a limited number of posts

As a consequence of the Template Hierarchy, home.php executes first. This means that you can write a home.php which calls query_posts() to retrieve a particular page and set that to be your front page. Without any plugins or hacks, you have got a mechanism to run, show and maintain a non-bloggy front page.

More useful perhaps would be to take advantage of WP’s Page functionality and use that for your front page. You could set your "about page" to be the entry point or maybe your site's colophon. You might even do something a bit more dynamic and set a custom page that shows a list of the latest comments, posts, categories and archives.

For multiple posts/pages, two more options exist:

• 'post__in' => array(1,2,3) - lets you directly specify a number of posts to retrieve
• 'post__not_in' => array(1,2,3) - exclusion lets you directly specify a number of posts NOT to retrieve

For sticky posts (available with WordPress Version 2.7):

• array('post__in'=>get_option('sticky_posts')) - returns array of all sticky posts

Time Parameters

Retrieve posts belonging to a certain time period.

• hour=
• minute=
• second=
• day= - day of the month; shows all posts made, for example on the 15th.
• monthnum=
• year=

Page Parameters

• paged=2 - show the posts that would normally show up just on page 2 when using the "Older Entries" link.
• posts_per_page=10 - number of posts to show per page; a value of -1 will show all posts.
• 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('showposts=5&offset=1');

Orderby Parameters

Sort retrieved posts by this field.

• orderby=author
• orderby=date
• orderby=category
• orderby=title
• orderby=modified
• orderby=modified
• orderby=menu_order
• orderby=parent
• orderby=ID
• orderby=rand

Also consider order parameter of "ASC" or "DESC"

Custom field Parameters

Retrieve posts based on a custom field set in the post

Both the meta_key and meta_value need to be set.

• meta_key=
• meta_value=

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),'showposts'=>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.