Add "Category" to Mysql Query

Question

i need your help :)

I've made this custom Mysql query on WordPress:

    $querystr = "
   SELECT  DISTINCT meta_value  FROM $wpdb->postmeta WHERE post_id IN(     
   SELECT DISTINCT wpostmeta.post_id
   FROM $wpdb->posts wposts, $wpdb->postmeta wpostmeta
   WHERE wposts.ID = wpostmeta.post_id 
   AND wpostmeta.meta_key  = 'color' 
   AND wpostmeta.meta_value  = 'red' 
   AND wposts.post_type = 'post' ) AND meta_key ='size' 
   ORDER BY RAND()
   LIMIT 4
   ";

How can i ADD in the query search for "Category name" or "Category ID" ?

Cheers ;)

Answer 1

If I'm not missing something, the below should work for you. It is pretty much straight from the Codex: WP_Query - Custom Field Parameters. Do it like this:

$args = array(
    'post_type' => 'post',
    'meta_query' => array(
        'relation' => 'AND',
        array(
            'key' => 'color',
            'value' => 'red',
            'compare' => '='
        ),
        array(
            'key' => 'size',
            'compare' => 'EXISTS'
        )
    )
);
$query = new WP_Query( $args );

Additional resources on here:

• Meta_query compare operator explanation
• Query posts only with featured image
• there are more, just use the search

Answer 2

To ADD in the query search for "Category name" or "Category ID" you have to apply inner join with ( wp_term_relationships ).

Pls try this

$category_id is your category id

<?php 

$args = array(
    'post_type' => 'post',
    'meta_query' => array(
        'relation' => 'AND',
        array(
            'key' => 'color',
            'value' => 'red',
            'compare' => '='
        ),
        array(
            'key' => 'size',
            'compare' => 'EXISTS'
        )
    ),
    'tax_query' => array(
                            'relation' => 'AND',
                array(
                    'taxonomy' => 'category',
                    'field' => 'id',
                    'terms' => $category_id,
                    'operator'  => 'IN'
                )),
);
$query = new WP_Query( $args );

?>