什么时候应该使用WP_Query vs query_posts（）vs get_posts（）？

• query_posts() 过于简单和通过用查询的新实例替换页面的主查询的一种有问题的方式来修改页面.它效率低下(重新运行SQL查询),并且在某些情况下(特别是在处理帖子分页时,通常会完全失败).任何现代WP代码都应使用更可靠的方法,例如使用 pre_get_posts 挂钩. TL; DR 永远不要使用query_posts().

• get_posts() 在用法上非常相似并接受相同的参数(有一些细微差别,例如不同的默认值),但是返回一个帖子数组,不修改全局变量,并且可以在任何地方使用.

• WP_Query 是同时支持这两个功能的类场景,但是您也可以创建和使用自己的实例.更加复杂,限制更少,在任何地方都可以安全使用.

• query_posts() is overly simplistic and a problematic way to modify the main query of a page by replacing it with new instance of the query. It is inefficient (re-runs SQL queries) and will outright fail in some circumstances (especially often when dealing with posts pagination). Any modern WP code should use more reliable methods, like making use of the pre_get_posts hook, for this purpose. TL;DR don't use query_posts() ever.

• get_posts() is very similar in usage and accepts the same arguments (with some nuances, like different defaults), but returns an array of posts, doesn't modify global variables and is safe to use anywhere.

• WP_Query is the class that powers both behind the scenes, but you can also create and work with your own instance of it. A bit more complex, fewer restrictions, also safe to use anywhere.

query_posts -您永远不要使用 query_posts .除了@Rarst所说的以外, query_posts 的真正大问题是,它破坏了主查询对象(存储在 $ wp_query 中).许多插件和自定义代码都依赖于主查询对象,因此破坏主查询对象意味着您正在破坏插件和自定义代码的功能.所有重要的分页功能只是其中一个功能,因此,如果中断主查询,则会中断分页.

要证明 query_posts 在任何模板上有多糟糕,请执行以下操作并比较结果

  var_dump($ wp_query);
query_posts('＆amp;posts_per_page=-1');
var_dump($ wp_query);
 

get_posts 和 WP_Query 是构造次要查询的正确方法(类似的相关帖子,滑块,特色内容和静态首页上的内容 ).应该注意的是,您不应使用这两种方法中的任何一种来支持主页,单页或任何类型的存档页面上的主查询,因为这会破坏页面功能.如果需要修改主查询,请使用pre_get_posts 进行修改,而不要使用自定义查询. ( 更新: 有关静态首页和真实页面,请参见使用pre_get_posts在真实页面和静态首页上 *)

本质上,主查询使用 WP_Query ,get_posts 也使用 WP_Query ,但是尽管get_posts()使用 WP_Query ,有一些区别

• get_posts 比 WP_Query 快.保证金取决于网站的总帖子数.原因是get_posts 通过'no_found_rows'=＆gt;true 默认为 WP_Query ,可跳过/合法中断分页.使用'no_found_rows'=＆gt;true , WP_Query 获取查询的帖子数量,然后进行纾困,默认情况下,它将进一步搜索与查询匹配的所有帖子,以计算分页.

  由于这个原因,get_posts()仅应用于非分页查询.对get_posts 进行分页确实是一大麻烦. WP_Query 应该用于所有分页查询

• get_posts()不受posts _ * 过滤器的影响,其中 WP_Query 受这些过滤器的影响.原因是默认情况下,get_posts 通过'suppress_filters'=＆gt;.true 到 WP_Query

• get_posts 有几个额外的参数,例如include ,exclude ,numberposts 和类别.在将这些参数传递给 WP_Query 之前,确实将其更改为 WP_Query 的有效参数. include 更改为post__in , Exclude 更改为post__not_in ,类别更改为 cat 和numberposts 放入posts_per_page .请注意,所有可以传递给 WP_Query 的参数与get_posts 一起使用,您可以忽略和不使用get_posts

  的默认参数

• get_posts 仅返回 WP_Query 的 $posts 属性,而 WP_Query 返回完整对象.当涉及条件,分页和可在循环内使用的其他有用信息时,该对象非常有用.

• get_posts 不使用循环,而是使用foreach 循环显示帖子.另外,默认情况下没有模板标签可用.必须使用 setup_postdata($post)使模板标签可用. WP_Query 使用循环,并且默认情况下模板模板可用

• get_posts 通过'ignore_sticky_posts'=＆gt; 1 到 WP_Query ,因此默认情况下get_posts 会忽略粘性帖子

基于上述内容,您可以使用get_posts 还是 WP_Query 以及查询中实际需要的内容.以上内容将指导您进行选择

query_posts - You should never ever use query_posts. Apart from what @Rarst has said, the really big issue with query_posts is, it breaks the main query object ( stored in $wp_query ). A lot of plugins and custom code relies on the main query object, so breaking the main query object means that you are breaking the functionalities of plugins and custom code. Just one such function is the all important pagination function, so if you break the main query, you break pagination.

To prove how bad query_posts is, on any template, do the following and compare the results

var_dump( $wp_query );
query_posts( '&posts_per_page=-1' );
var_dump( $wp_query );

get_posts and WP_Query are the correct way to construct secondary queries ( like related posts, sliders, featured content and content on static front pages ) with. It should be noted, you should not use any of the two in favor of the main query on the home page, single page or any type of archive page as it will break page functionality. If you need to modify the main query, use pre_get_posts to do so, and not a custom query. (UPDATE: For static front pages and true pages, see Using pre_get_posts on true pages and static front pages*)

In essence, WP_Query is used by the main query and is also used by get_posts, but although get_posts() uses WP_Query, there are a few differences

• get_posts are faster than WP_Query. The margin depends on the amount of total posts of the site. The reason for this is, get_posts passes 'no_found_rows' => true by default to WP_Query which skips/legally breaks pagination. With 'no_found_rows' => true, WP_Query gets the amount of posts queried, then bails out, where by default, it further search for all posts matching the query in order to calculate pagination.

  For this reason, get_posts() should be used for non paginated queries only. Paginating get_posts is really one big mess. WP_Query should be used for all paginated queries

• get_posts() aren't influenced by the posts_* filters where WP_Query gets influenced by these filters. The reason is that get_posts, by default, passes 'suppress_filters' => true to WP_Query

• get_posts has a couple of extra parameters like include, exclude, numberposts and category. These parameters do get changed into valid parameters for WP_Query before being passed to WP_Query. include gets changed into post__in, exclude into post__not_in, category into cat and numberposts into posts_per_page. Just a note, all of the parameters that can be passed to WP_Query works with get_posts, you can ignore and not use the default parameters of get_posts

• get_posts returns just the $posts property of WP_Query while WP_Query returns the complete object. This object is quite useful when it comes to conditionals, pagination and other useful info that can be used inside the loop.

• get_posts doesn't use the loop, but a foreach loop to display posts. Also, no template tags are available by default. setup_postdata( $post ) has to be used to make the template tags available. WP_Query uses the loop and template tags are available by default

• get_posts passes 'ignore_sticky_posts' => 1 to WP_Query, so get_posts by default ignores sticky posts

Based on the above, whether to use get_posts or WP_Query is up to you and what do you actually need from the query. The above should guide you in your choice

基本区别是query_posts()实际上仅用于修改当前Loop.完成后,有必要重置循环并以愉快的方式发送循环.仅仅因为您的"查询"基本上是您传递给函数的URL字符串,这种方法也更易于理解,就像这样:

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

另一方面,与query_posts()相比,query_posts()更像是一种通用工具,更像直接编写MySQL查询.您还可以在任何地方(不仅是在循环中)使用它,它不会干扰任何当前正在运行的帖子查询.

随着时间的流逝,我倾向于更频繁地使用query_posts().确实,这取决于您的具体情况.

The basic difference is that query_posts() is really only for modifying the current Loop. Once you're done it's necessary to reset the loop and send it on its merry way. This method is also a little easier to understand, simply because your "query" is basically a URL string that you pass to the function, like so:

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

On the other hand, WP_Query is more of a general purpose tool, and is more like directly writing MySQL queries than query_posts() is. You can also use it anywhere (not just in the Loop) and it doesn't interfere with any currently running post queries.

I tend to use WP_Query more often, as it happens. Really, it's going to come down to your specific case.

根本不需要使用query_posts().它所做的只是实例化一个新的WP_Query对象,然后将该新对象重新分配给global wp_query.

作为参考,以下是实际的query_posts()函数.

  function query_posts($query) {
        $GLOBALS['wp_query'] = new WP_Query();
        return $GLOBALS['wp_query']->query($query);
    }
 

如果要创建深度自定义查询脚本,请实例化自己的WP_Query对象.或使用get_posts()(如果您需要做的只是在这里和那里进行一些灯光操作).

无论哪种情况,我都强烈建议您帮个忙,转到wp_includes/query.php并仔细阅读WP_Query类.

There is simply no need to use query_posts(). All it does is instantiates a new WP_Query object and reassigns that new object to global wp_query.

For reference, the following is that actual query_posts() function.

 function query_posts($query) {
        $GLOBALS['wp_query'] = new WP_Query();
        return $GLOBALS['wp_query']->query($query);
    }

Instantiate your own WP_Query object if you want to create an in depth custom query script. Or use get_posts() if all you need to do is some light manipulation here and there.

In either case, I highly recommend doing yourself a favor and going to wp_includes/query.php and perusing the WP_Query class.

请确保在使用wp_reset_query()后再使用query_posts(),因为这也会影响其他查询结果.

Make sure that you use wp_reset_query() after using query_posts() because it will affect other query result also.

如果我没看错的话,本质上,"循环"是在核心文件中执行WP_Query,但是以一种更易于理解的方式进行.

If I recall reading right, essentially "the loop" is doing WP_Query in the core files, but in an easier to understand way.

• query_posts():只有在需要修改main的情况下才可以使用查询.它设置了很多全局变量；
• get_posts():在机制上非常相似,接受相同的参数,但返回数组的帖子
• WP_Query :您可以创建并使用其自己的对象.位更加复杂,限制更少,可以在任何地方使用.

• query_posts(): might be used in one and only case if you need to modify main query . It sets a lot of global variables;
• get_posts(): it is very similar in mechanics and accepts same arguments, but returns array of posts
• WP_Query:  you can create and work with own object of it. Bit more complex, less restrictions, it is safe to use anywhere.