Replace Main Query With Custom Query

Question

I want to replace the main query with my own custom query. The thing is I don't want to go through the hassle of manual paging. I know there's a filter posts_results but I'm not sure how to use it exactly, I couldn't find a bunch of info on it. It looks like pre_get_posts is only altering the query instead of replacing it entirely. I tried to just dump my query into $posts but then I lost paging. Is there a way around this?

I'm using $posts = wpdb->get_results($query); to replace the main query with my own.

$query is my custom SQL. I'm adding the snippet above right under get_header(). I'm trying to edit the main query on my custom taxonomy page: taxonomy-mytax.php.

The Situation

Currently my client has Manufacturers (Taxonomy) and Products (Taxonomy) then an actual Product (Custom Post Type). They requested to show Product posts (on the product category page - taxonomy-producttax.php) in an order by their most favorable Manufacturer (taxonomy). So I added an extra field into the manufacturer taxonomy where they can set a number that declares an order. This number is saved into $wpdb->terms.term_group. Now on the Product Category page I'm trying to replace the main query entirely with a brand new query that will get all the products and put them in order by a manufacturers term_group. Both Product and Manufactuers (both taxonomies) have an order, and both are put into $wpdb->terms.term_gruop which was troublesome. I created a custom query that works, and will show posts in manufacturers term_group order . I just need to replace the main query on taxonomy-producttax.php with my custom SQL query, but I didn't want to get into manual paging I wanted to use anything Wordpress has built in to help me.

Answer 1

You cannot replace the main query with the output of $wpdb. The main query is a WP_Query object. $wpdb returns a simple array or object, but not a WP_Query object.

Even if you could shove raw SQL into a query (something in the back of my head makes me think you can but I can't swear to it) it is not advisable. Try var_dump($wp_query); and you will see that there is a lot going on besides just a SQL query. For the object to work--including the pagination that you want-- all of that other stuff has to be set correctly.

You do need to use pre_get_posts and perhaps other query filters like posts_where to alter the WP_Query object, not replace it. Without knowing the details as @Milo and @ChipBennett have requested but you are hesitant to provide, it is not going to be possible to give you much more of an answer.

Answer 2

Well it is a taxonomy archive page. What my query does is order posts by a category order that the users sets... So I would need to change the select, the join, the where, the order.

Without seeing your actual code, it's difficult to give a more-precise answer. However, besides the pre_get_posts action hook, WordPress provides several filters for manipulating the query even earlier:

• posts_join
• posts_orderby
• posts_where

There is not likely any real reason that you can't manipulate the main query to suit your needs:

So I added an extra field into the manufacturer taxonomy where they can set a number that declares an order. This number is saved into $wpdb->terms.term_group. Now on the Product Category page I'm trying to replace the main query entirely with a brand new query that will get all the products and put them in order by a manufacturers term_group. Both Product and Manufactuers (both taxonomies) have an order, and both are put into $wpdb->terms.term_gruop which was troublesome. I created a custom query that works, and will show posts in manufacturers term_group order .