wp_query是一個wordpress用於復雜請求的的一個類，看到query懂開發的人就會反應這個是數據庫查詢的一個類，這個類可謂是非常有用的，可以幫助我們做很多復雜的查詢。
wp_query的使用方法也很簡單：
$query = new WP_Query( 'author=123' ); // 查詢單個作者的文章 $query = new WP_Query( 'author_name=rami' ); // 根據用戶名查找 $query = new WP_Query( 'author=2,6,17,38' ); // 查詢多個人的文章 $query = new WP_Query( 'author=-12' ); // 查詢不屬於某個人的文章 可以通過減號“-”來排除某位作者。 $query = new WP_Query( 'cat=4' ); // 按分類ID $query = new WP_Query( 'category_name=staff' ); //查詢某個分類下的文章（包含它的子分類） $query = new WP_Query( 'category__in=4' ); //查詢某個分類下的文章（不包含它的子分類） $query = new WP_Query( 'cat=2,6,17,38' ); // ID 類似的，查詢多個分類下的文章 $query = new WP_Query( 'category_name=staff,news' ); // slug 類似的，查詢多個分類下的文章 $query = new WP_Query( 'cat=-12,-34,-56' ); //不包含某個分類 // 查詢同時屬於多個分類的文章 $query = new WP_Query( array( 'category__and' => array( 2, 6 ) ) ); // 2 and 6 $query = new WP_Query( array( 'category__in' => array( 2, 6 ) ) ); // 2 or 6
通過標簽查詢
可通過標簽查詢的條件包括：tag, tag_id, tag__and, tag__in, tag__not_in, tag_slug__and, tag_slug__in。
對應到上面分類的查詢方法，不難理解每個條件如何使用，我不一一舉例了。（注意：名字中沒有slug的，用tag的id查詢)。
簡單使用示例：
<?php // 調用的分類4，可以修改分類id 顯示的前兩篇文章，可以修改顯示篇數 $where = array('cat' =>'4','posts_per_page' =>'2',); $the_query = new WP_Query($where); // 開始循環 if ( $the_query->have_posts() ) {//如果找到了結果，便輸出以下內容 echo '<ul>'; while ( $the_query->have_posts() ) {//再次判斷是否有結果 $the_query->the_post();//不用問為什么，每次都要寫這個； ?> <li><a href="<?php the_permalink();?>"><?php the_title();?></a></li> <?php } echo '</ul>'; } else { // 如果沒有找到任何結果，就輸出這個 } wp_reset_postdata();//不用問為什么，每次都記得寫就好 ?>
簡單示例：
<?php $args = array( // 用於查詢的參數或者參數集合 ); // 自定義查詢 $the_query = new WP_Query( $args ); // 判斷查詢的結果，檢查是否有文章 if ( $the_query->have_posts() ) : // 通過查詢的結果，開始主循環 while ( $the_query->have_posts() ) : $the_query->the_post(); //獲取到特定的文章 // 要輸出的內容，如標題、日期等 endwhile; endif; // 重置請求數據 wp_reset_postdata(); ?>
深入查看wp_query類
<?php $args = array( //作者參數 - Show posts associated with certain author. //http://codex.wordpress.org/Class_Reference/WP_Query#Author_Parameters 'author' => '1,2,3,', //(int) - use author id [use minus (-) to exclude authors by ID ex. 'author' => '-1,-2,-3,'] 'author_name' => 'luetkemj', //(string) - use 'user_nicename' (NOT name) 'author__in' => array( 2, 6 ), //(array) - use author id (available with Version 3.7). 'author__not_in' => array( 2, 6 ), //(array)' - use author id (available with Version 3.7). //類別參數 - Show posts associated with certain categories. //http://codex.wordpress.org/Class_Reference/WP_Query#Category_Parameters 'cat' => 5,//(int) - use category id. 'category_name' => 'staff, news', //(string) - Display posts that have these categories, using category slug. 'category_name' => 'staff+news', //(string) - Display posts that have "all" of these categories, using category slug. 'category__and' => array( 2, 6 ), //(array) - use category id. 'category__in' => array( 2, 6 ), //(array) - use category id. 'category__not_in' => array( 2, 6 ), //(array) - use category id. //標簽參數 - Show posts associated with certain tags. //http://codex.wordpress.org/Class_Reference/WP_Query#Tag_Parameters 'tag' => 'cooking', //(string) - use tag slug. 'tag_id' => 5, //(int) - use tag id. 'tag__and' => array( 2, 6), //(array) - use tag ids. 'tag__in' => array( 2, 6), //(array) - use tag ids. 'tag__not_in' => array( 2, 6), //(array) - use tag ids. 'tag_slug__and' => array( 'red', 'blue'), //(array) - use tag slugs. 'tag_slug__in' => array( 'red', 'blue'), //(array) - use tag slugs. //分類參數（自定義分類法） - Show posts associated with certain taxonomy. //http://codex.wordpress.org/Class_Reference/WP_Query#Taxonomy_Parameters //Important Note: tax_query takes an array of tax query arguments arrays (it takes an array of arrays) //This construct allows you to query multiple taxonomies by using the relation parameter in the first (outer) array to describe the boolean relationship between the taxonomy queries. 'tax_query' => array( //(array) - use taxonomy parameters (available with Version 3.1). 'relation' => 'AND', //(string) - Possible values are 'AND' or 'OR' and is the equivalent of running a JOIN for each taxonomy array( 'taxonomy' => 'color', //(string) - Taxonomy. 'field' => 'slug', //(string) - Select taxonomy term by ('id' or 'slug') 'terms' => array( 'red', 'blue' ), //(int/string/array) - Taxonomy term(s). 'include_children' => true, //(bool) - Whether or not to include children for hierarchical taxonomies. Defaults to true. 'operator' => 'IN' //(string) - Operator to test. Possible values are 'IN', 'NOT IN', 'AND'. ), array( 'taxonomy' => 'actor', 'field' => 'id', 'terms' => array( 103, 115, 206 ), 'include_children' => false, 'operator' => 'NOT IN' ) ), //文章和頁面參數 - Display content based on post and page parameters. //http://codex.wordpress.org/Class_Reference/WP_Query#Post_.26_Page_Parameters 'p' => 1, //(int) - use post id. 'name' => 'hello-world', //(string) - use post slug. 'page_id' => 1, //(int) - use page id. 'pagename' => 'sample-page', //(string) - use page slug. 'pagename' => 'contact_us/canada', //(string) - Display child page using the slug of the parent and the child page, separated ba slash 'post_parent' => 1, //(int) - use page id. Return just the child Pages. (Only works with heirachical post types.) 'post_parent__in' => array(1,2,3) //(array) - use post ids. Specify posts whose parent is in an array. NOTE: Introduced in 3.6 'post_parent__not_in' => array(1,2,3), //(array) - use post ids. Specify posts whose parent is not in an array. 'post__in' => array(1,2,3), //(array) - use post ids. Specify posts to retrieve. ATTENTION If you use sticky posts, they will be included (prepended!) in the posts you retrieve whether you want it or not. To suppress this behaviour use ignore_sticky_posts 'post__not_in' => array(1,2,3), //(array) - use post ids. Specify post NOT to retrieve. //NOTE: you cannot combine 'post__in' and 'post__not_in' in the same query //////Password Parameters - Show content based on post and page parameters. Remember that default post_type is only set to display posts but not pages. //http://codex.wordpress.org/Class_Reference/WP_Query#Password_Parameters 'has_password' => true, //(bool) - available with Version 3.9 //true for posts with passwords; //false for posts without passwords; //null for all posts with and without passwords 'post_password' => 'multi-pass', //(string) - show posts with a particular password (available with Version 3.9) //////類型狀態參數 - Show posts associated with certain type or status. //http://codex.wordpress.org/Class_Reference/WP_Query#Type_Parameters 'post_type' => array( //(string / array) - use post types. Retrieves posts by Post Types, default value is 'post'; 'post', // - a post. 'page', // - a page. 'revision', // - a revision. 'attachment', // - an attachment. The default WP_Query sets 'post_status'=>'published', but atchments default to 'post_status'=>'inherit' so you'll need to set the status to 'inherit' or 'any'. 'my-post-type', // - Custom Post Types (e.g. movies) ), //NOTE: The 'any' keyword available to both post_type and post_status queries cannot be used within an array. 'post_type' => 'any', // - retrieves any type except revisions and types with 'exclude_from_search' set to true. //////Type & Status Parameters - Show posts associated with certain type or status. //http://codex.wordpress.org/Class_Reference/WP_Query#Status_Parameters 'post_status' => array( //(string / array) - use post status. Retrieves posts by Post Status, default value i'publish'. 'publish', // - a published post or page. 'pending', // - post is pending review. 'draft', // - a post in draft status. 'auto-draft', // - a newly created post, with no content. 'future', // - a post to publish in the future. 'private', // - not visible to users who are not logged in. 'inherit', // - a revision. see get_children. 'trash' // - post is in trashbin (available with Version 2.9). ), //NOTE: The 'any' keyword available to both post_type and post_status queries cannot be used within an array. 'post_status' => 'any', // - retrieves any status except those from post types with 'exclude_from_search' set to true. //////分頁參數 //http://codex.wordpress.org/Class_Reference/WP_Query#Pagination_Parameters 'posts_per_page' => 10, //(int) - number of post to show per page (available with Version 2.1). Use 'posts_per_page' => -1 to show all posts. //Note: if the query is in a feed, wordpress overwrites this parameter with the stored 'posts_per_rss' option. Treimpose the limit, try using the 'post_limits' filter, or filter 'pre_option_posts_per_rss' and return -1 'posts_per_archive_page' => 10, //(int) - number of posts to show per page - on archive pages only. Over-rides showposts anposts_per_page on pages where is_archive() or is_search() would be true 'nopaging' => false, //(bool) - show all posts or use pagination. Default value is 'false', use paging. 'paged' => get_query_var('paged'), //(int) - number of page. Show the posts that would normally show up just on page X when usinthe "Older Entries" link. //NOTE: Use get_query_var('page'); if you want your query to work in a Page template that you've set as your static front page. The query variable 'page' holds the pagenumber for a single paginated Post or Page that includes the lt;!--nextpage--gt; Quicktag in the post content. 'nopaging' => false, // (boolean) - show all posts or use pagination. Default value is 'false', use paging. 'posts_per_archive_page' => 10, // (int) - number of posts to show per page - on archive pages only. Over-rides posts_per_page and showposts on pages where is_archive() or is_search() would be true. 'offset' => 3, // (int) - number of post to displace or pass over. // Warning: Setting the offset parameter overrides/ignores the paged parameter and breaks pagination. for a workaround see: http://codex.wordpress.org/Making_Custom_Queries_using_Offset_and_Pagination // The 'offset' parameter is ignored when 'posts_per_page'=>-1 (show all posts) is used. 'paged' => get_query_var('paged'), //(int) - number of page. Show the posts that would normally show up just on page X when usinthe "Older Entries" link. //NOTE: This whole paging thing gets tricky. Some links to help you out: // http://codex.wordpress.org/Function_Reference/next_posts_link#Usage_when_querying_the_loop_with_WP_Query // http://codex.wordpress.org/Pagination#Troubleshooting_Broken_Pagination 'page' => get_query_var('page'), // (int) - number of page for a static front page. Show the posts that would normally show up just on page X of a Static Front Page. //NOTE: The query variable page holds the pagenumber for a single paginated Post or Page that includes the < !--nextpage--> Quicktag in the post content. 'ignore_sticky_posts' => false, // (boolean) - ignore sticky posts or not (available with Version 3.1, replaced caller_get_posts parameter). Default value is 0 - don't ignore sticky posts. Note: ignore/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. //////排序參數 - Sort retrieved posts. //http://codex.wordpress.org/Class_Reference/WP_Query#Order_.26_Orderby_Parameters 'order' => 'DESC', //(string) - Designates the ascending or descending order of the 'orderby' parameter. Default to 'DESC'. //Possible Values: //'ASC' - ascending order from lowest to highest values (1, 2, 3; a, b, c). //'DESC' - descending order from highest to lowest values (3, 2, 1; c, b, a). 'orderby' => 'date', //(string) - Sort retrieved posts by parameter. Defaults to 'date'. One or more options can be passed. EX: 'orderby' => 'menu_order title' //Possible Values: //'none' - No order (available with Version 2.8). //'ID' - Order by post id. Note the captialization. //'author' - Order by author. //'title' - Order by title. //'name' - Order by post name (post slug). //'date' - Order by date. //'modified' - Order by last modified date. //'parent' - Order by post/page parent id. //'rand' - Random order. //'comment_count' - Order by number of comments (available with Version 2.9). //'menu_order' - Order by Page Order. Used most often for Pages (Order field in the EdiPage Attributes box) and for Attachments (the integer fields in the Insert / Upload MediGallery dialog), but could be used for any post type with distinct 'menu_order' values (theall default to 0). //'meta_value' - Note that a 'meta_key=keyname' must also be present in the query. Note alsthat the sorting will be alphabetical which is fine for strings (i.e. words), but can bunexpected for numbers (e.g. 1, 3, 34, 4, 56, 6, etc, rather than 1, 3, 4, 6, 34, 56 as yomight naturally expect). //'meta_value_num' - Order by numeric meta value (available with Version 2.8). Also notthat a 'meta_key=keyname' must also be present in the query. This value allows for numericasorting as noted above in 'meta_value'. //'title menu_order' - Order by both menu_order AND title at the same time. For more info see: http://wordpress.stackexchange.com/questions/2969/order-by-menu-order-and-title //'post__in' - Preserve post ID order given in the post__in array (available with Version 3.5). //////日期參數 - Show posts associated with a certain time and date period. //http://codex.wordpress.org/Class_Reference/WP_Query#Date_Parameters 'year' => 2014, //(int) - 4 digit year (e.g. 2011). 'monthnum' => 4, //(int) - Month number (from 1 to 12). 'w' => 25, //(int) - Week of the year (from 0 to 53). Uses the MySQL WEEK command. The mode is dependenon the "start_of_week" option. 'day' => 17, //(int) - Day of the month (from 1 to 31). 'hour' => 13, //(int) - Hour (from 0 to 23). 'minute' => 19, //(int) - Minute (from 0 to 60). 'second' => 30, //(int) - Second (0 to 60). 'm' => 201404, //(int) - YearMonth (For e.g.: 201307). 'date_query' => array( //(array) - Date parameters (available with Version 3.7). //these are super powerful. check out the codex for more comprehensive code examples http://codex.wordpress.org/Class_Reference/WP_Query#Date_Parameters array( 'year' => 2014, //(int) - 4 digit year (e.g. 2011). 'month' => 4 //(int) - Month number (from 1 to 12). 'week' => 31 //(int) - Week of the year (from 0 to 53). 'day' => 5 //(int) - Day of the month (from 1 to 31). 'hour' => 2 //(int) - Hour (from 0 to 23). 'minute' => 3 //(int) - Minute (from 0 to 59). 'second' => 36 //(int) - Second (0 to 59). 'after' => 'January 1st, 2013', //(string/array) - Date to retrieve posts after. Accepts strtotime()-compatible string, or array of 'year', 'month', 'day' 'before' => array( //(string/array) - Date to retrieve posts after. Accepts strtotime()-compatible string, or array of 'year', 'month', 'day' 'year' => 2013, //(string) Accepts any four-digit year. Default is empty. 'month' => 2, //(string) The month of the year. Accepts numbers 1-12. Default: 12. 'day' => 28, //(string) The day of the month. Accepts numbers 1-31. Default: last day of month. ), 'inclusive' => true, //(boolean) - For after/before, whether exact value should be matched or not'. 'compare' => '=', //(string) - Possible values are '=', '!=', '>', '>=', '<', '<=', 'LIKE', 'NOT LIKE', 'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN', 'EXISTS' (only in WP >= 3.5), and 'NOT EXISTS' (also only in WP >= 3.5). Default value is '=' 'column' => 'post_date', //(string) - Column to query against. Default: 'post_date'. 'relation' => 'AND', //(string) - OR or AND, how the sub-arrays should be compared. Default: AND. ), ), //////自定義字段參數 - Show posts associated with a certain custom field. //http://codex.wordpress.org/Class_Reference/WP_Query#Custom_Field_Parameters 'meta_key' => 'key', //(string) - Custom field key. 'meta_value' => 'value', //(string) - Custom field value. 'meta_value_num' => 10, //(number) - Custom field value. 'meta_compare' => '=', //(string) - Operator to test the 'meta_value'. Possible values are '!=', '>', '>=', '<', or ='. Default value is '='. 'meta_query' => array( //(array) - Custom field parameters (available with Version 3.1). 'relation' => 'AND', //(string) - Possible values are 'AND', 'OR'. The logical relationship between each inner meta_query array when there is more than one. Do not use with a single inner meta_query array. array( 'key' => 'color', //(string) - Custom field key. 'value' => 'blue' //(string/array) - Custom field value (Note: Array support is limited to a compare value of 'IN', 'NOT IN', 'BETWEEN', or 'NOT BETWEEN') Using WP < 3.9? Check out this page for details: http://codex.wordpress.org/Class_Reference/WP_Query#Custom_Field_Parameters 'type' => 'CHAR', //(string) - Custom field type. Possible values are 'NUMERIC', 'BINARY', 'CHAR', 'DATE', 'DATETIME', 'DECIMAL', 'SIGNED', 'TIME', 'UNSIGNED'. Default value is 'CHAR'. The 'type' DATE works with the 'compare' value BETWEEN only if the date is stored at the format YYYYMMDD and tested with this format. //NOTE: The 'type' DATE works with the 'compare' value BETWEEN only if the date is stored at the format YYYYMMDD and tested with this format. 'compare' => '=' //(string) - Operator to test. Possible values are '=', '!=', '>', '>=', '<', '<=', 'LIKE', 'NOT LIKE', 'IN', 'NOT IN', 'BETWEEN', 'NOT BETWEEN', 'EXISTS' (only in WP >= 3.5), and 'NOT EXISTS' (also only in WP >= 3.5). Default value is '='. ), array( 'key' => 'price', 'value' => array( 1,200 ), 'compare' => 'NOT LIKE' ) ), //////Permission Parameters - Display published posts, as well as private posts, if the user has the appropriate capability: //http://codex.wordpress.org/Class_Reference/WP_Query#Permission_Parameters 'perm' => 'readable' //(string) Possible values are 'readable', 'editable' //////Caching Parameters //http://codex.wordpress.org/Class_Reference/WP_Query#Caching_Parameters //NOTE Caching is a good thing. Setting these to false is generally not advised. 'cache_results' => true, //(bool) Default is true - Post information cache. 'update_post_term_cache' => true, //(bool) Default is true - Post meta information cache. 'update_post_meta_cache' => true, //(bool) Default is true - Post term information cache. 'no_found_rows' => false, //(bool) Default is false. WordPress uses SQL_CALC_FOUND_ROWS in most queries in order to implement pagination. Even when you don’t need pagination at all. By Setting this parameter to true you are telling wordPress not to count the total rows and reducing load on the DB. Pagination will NOT WORK when this parameter is set to true. For more information see: http://flavio.tordini.org/speed-up-wordpress-get_posts-and-query_posts-functions //////Search Parameter //http://codex.wordpress.org/Class_Reference/WP_Query#Search_Parameter 's' => $s, //(string) - Passes along the query string variable from a search. For example usage see: http://www.wprecipes.com/how-to-display-the-number-of-results-in-wordpress-search 'exact' => true, //(bool) - flag to make it only match whole titles/posts - Default value is false. For more information see: https://gist.github.com/2023628#gistcomment-285118 'sentence' => true, //(bool) - flag to make it do a phrase search - Default value is false. For more information see: https://gist.github.com/2023628#gistcomment-285118 //////Post Field Parameters //For more info see: http://codex.wordpress.org/Class_Reference/WP_Query#Return_Fields_Parameter //also https://gist.github.com/luetkemj/2023628/#comment-1003542 'fields' => 'ids' //(string) - Which fields to return. All fields are returned by default. //Possible values: //'ids' - Return an array of post IDs. //'id=>parent' - Return an associative array [ parent => ID, … ]. //Passing anything else will return all fields (default) - an array of post objects. //////Filters //For more information on available Filters see: http://codex.wordpress.org/Class_Reference/WP_Query#Filters ); ?>
具體使用示例：
<?php $args = array('post_type'=>'post','showposts'=>'10','posts_per_page'=>'10','paged'=>get_query_var('paged')); $recendposts = new WP_Query( $args ); if($recendposts->have_posts()) : while($recendposts->have_posts()) : $recendposts->the_post(); ?> <li><a href="<?php the_permalink() ?>" title="<?php the_title(); ?>"><?php the_title(); ?></a></li> <?php endwhile; endif; wp_reset_postdata(); ?>
一個非常有用的查詢，看得懂的拿去：
<?php // $where = array('cat'=>1,'posts_per_page'=2); // $where = array('author'=>1); $where = array('s'=>'工具','post_type'=>'post'); $the_query = new WP_Query( $where ); var_dump($the_query); // 開始循環 if($the_query->have_posts()){//如果找到了結果，便輸出以下內容 echo '<ul>'; while ( $the_query->have_posts() ) { //再次判斷是否有結果 $the_query->the_post(); //不用問為什么，每次都要寫這個； ?> <li><a href="<?php the_permalink();?>"><?php the_title();?></a></li> <?php } echo '</ul>'; } else { echo "沒有找到相關的文章"; } wp_reset_postdata(); ?>
結合PHP的流程控制對上面的代碼進行改造：
<?php $where = array('s'=>'工具','post_type'=>'post'); ?> <?php $the_query = new WP_Query( $where ); ?> <?php if($the_query->have_posts()):?> <?php while ($the_query->have_posts()) : $the_query->the_post();?> <a href="<?php the_permalink();?>"><?php the_title();?></a><br> <?php endwhile; ?> <?php else : ?> //此處顯示未找到文章時的信息，比如404相關 <?php endif; ?>
查詢5條瀏覽量最多的：
<?php $where = array('s'=>'工具','post_type'=>'post','order'=>'DESC','meta_key'=>'views','orderby'=>'meta_value_num','posts_per_page'=>1); ?> <?php $the_query = new WP_Query( $where ); ?> <?php if($the_query->have_posts()):?> <?php while ($the_query->have_posts()) : $the_query->the_post();?> <a href="<?php the_permalink();?>"><?php the_title();?></a><br> <?php endwhile; ?> <?php else : ?> //此處顯示未找到文章時的信息，比如404相關 <?php endif; ?>