Retrieve custom post types by custom taxonomies with WP_Query

Question

I am trying to filter custom post type data using ajax. For that, I display some custom taxonomies as select tags.

I've been trying for 6 hours to retrieve custom post types using WP_Query with these custom taxonomy arguments, but I am not able to get the query working.

This is my custom post type:

function cpt_retiro() {
$labels = array(
    'name'                  => _x( 'Retiros', 'Post Type General Name', 'break-breath' ),
    'singular_name'         => _x( 'Retiro', 'Post Type Singular Name', 'break-breath' ),
    'menu_name'             => __( 'Retiros', 'break-breath' ),
    'name_admin_bar'        => __( 'Retiros', 'break-breath' ),
    'archives'              => __( 'Archivos del retiro', 'break-breath' ),
    'attributes'            => __( 'Atributos del retiro', 'break-breath' ),
    'parent_item_colon'     => __( 'Elemento padre', 'break-breath' ),
    'all_items'             => __( 'Todos los retiros', 'break-breath' ),
    'add_new_item'          => __( 'Añadir nuevo retiro', 'break-breath' ),
    'add_new'               => __( 'Añadir nuevo', 'break-breath' ),
    'new_item'              => __( 'Nuevo retiro', 'break-breath' ),
    'edit_item'             => __( 'Editar retiro', 'break-breath' ),
    'update_item'           => __( 'Actualizar retiro', 'break-breath' ),
    'view_item'             => __( 'Ver retiro', 'break-breath' ),
    'view_items'            => __( 'Ver retiros', 'break-breath' ),
    'search_items'          => __( 'Buscar retiro', 'break-breath' ),
    'not_found'             => __( 'No se han encontrado retiros', 'break-breath' ),
    'not_found_in_trash'    => __( 'No se han encontrado retiros en la papelera', 'break-breath' ),
    'featured_image'        => __( 'Imagen destacada', 'break-breath' ),
    'set_featured_image'    => __( 'Seleccionar imagen destacada', 'break-breath' ),
    'remove_featured_image' => __( 'Borrar imagen destacada', 'break-breath' ),
    'use_featured_image'    => __( 'Establecer como imagen destacada', 'break-breath' ),
    'insert_into_item'      => __( 'Insertar en retiro', 'break-breath' ),
    'uploaded_to_this_item' => __( 'Subido a este retiro', 'break-breath' ),
    'items_list'            => __( 'Listado de retiros', 'break-breath' ),
    'items_list_navigation' => __( 'Navegación entre retiros', 'break-breath' ),
    'filter_items_list'     => __( 'Filtrar retiros', 'break-breath' ),
);
$args = array(
    'label'                 => __( 'Retiro', 'break-breath' ),
    'description'           => __( 'Retiros', 'break-breath' ),
    'labels'                => $labels,
    'supports'              => array( 'title', 'editor', 'thumbnail', 'excerpt', 'comments' ),
    'taxonomies'            => array( 'category', 'post_tag', 'provincia', 'ciudad' ),
    'hierarchical'          => true,
    'show_ui'               => true,
    'show_in_menu'          => true,
    'menu_position'         => 5,
    'menu_icon'             => 'dashicons-location-alt',
    'show_in_admin_bar'     => true,
    'show_in_nav_menus'     => true,
    'can_export'            => true,
    'has_archive'           => true,
    'exclude_from_search'   => false,
    'publicly_queryable'    => true,
    'capability_type'       => 'page',
);
register_post_type( 'retiro', $args );}

add_action( 'init', 'cpt_retiro', 0 );

This is one of my registered taxonomies:

function taxonomia_provincia_retiro() {
$labels = array(
    'name'                       => _x( 'Provincias', 'Taxonomy General Name', 'break-breath' ),
    'singular_name'              => _x( 'Provincia', 'Taxonomy Singular Name', 'break-breath' ),
    'menu_name'                  => __( 'Provincias', 'break-breath' ),
    'all_items'                  => __( 'Todas las provincias', 'break-breath' ),
    'new_item_name'              => __( 'Añadir nuevo nombre de provincia', 'break-breath' ),
    'add_new_item'               => __( 'Añadir nueva provincia', 'break-breath' ),
    'edit_item'                  => __( 'Editar provincia', 'break-breath' ),
    'update_item'                => __( 'Actualizar provincia', 'break-breath' ),
    'view_item'                  => __( 'Ver provincia', 'break-breath' ),
    'separate_items_with_commas' => __( 'Separar provincias por comas', 'break-breath' ),
    'add_or_remove_items'        => __( 'Añadir o borrar provincias', 'break-breath' ),
    'choose_from_most_used'      => __( 'Elegir provincia entre las más usadas', 'break-breath' ),
    'popular_items'              => __( 'Provincias populares', 'break-breath' ),
    'search_items'               => __( 'Buscar provincias', 'break-breath' ),
    'not_found'                  => __( 'No se han encontrado provincias', 'break-breath' ),
    'no_terms'                   => __( 'No existen provincias', 'break-breath' ),
    'items_list'                 => __( 'Listado de provincias', 'break-breath' ),
    'items_list_navigation'      => __( 'Navegación entre provincias', 'break-breath' ),
);
$args = array(
    'labels'                     => $labels,
    'hierarchical'               => true,
    'public'                     => true,
    'show_ui'                    => true,
    'show_admin_column'          => true,
    'show_in_nav_menus'          => true,
    'show_tagcloud'              => true,
    'query_var'                  => true
);
register_taxonomy( 'provincia', array( 'retiro' ), $args );}

add_action( 'init', 'taxonomia_provincia_retiro', 0 );

So, the final result is:

Another example:

If i do this, It works fine:

$args = array('post_type' => 'retiro');
$query = new WP_Query($args);

But, when I try to do this as the codex says, it does not work:

$args = array(
'post_type' => 'retiro',
'tax_query' => array(
    array(
        'taxonomy' => 'provincia'
    ),
),);

$query = new WP_Query( $args );

I am getting crazy, what is wrong with this code?? Thanks in advance for helping me! Have a nice day!

Answer 1

You need to pass the field and terms to get this working the right way:

'tax_query' => array(
    'relation' => 'AND',
    array(
        'taxonomy' => 'provincia',
        'field'    => 'slug',
        'terms'    => array( 'term1', 'term2' ),
    ),
),

https://codex.wordpress.org/Class_Reference/WP_Query#Taxonomy_Parameters