How to query custom post types posts filtered by multiple custom taxonomies through a form selection

Question

I'm trying to create a sort of selection menu, in order to select custom posts by different custom taxonomies. I did the selection part, but I can't get to output my post and I can't understand where my mistakes are. What I have so fare: - Custom post type: "corsi"; - 5 different custom taxonomies: "prodotto", "livello", "ruolo", "stato"; - The selection form, made as a form, with radio button input and a bit of jQuery.

The form part

  <form id="regiration_form" novalidate action="<?php echo $current_url;?>" method="post">
    <fieldset>
        <div class="form-group">
            <h1>1</h1>
            <?php

    $prodotto_terms = get_terms( 'prodotto', array(
          'orderby'    => 'date',
          'order' => 'DESC',
          'hide_empty' => 0
        ) );
    ?>
                <?php foreach( $prodotto_terms as $term ) {
                          $term_link = get_term_link( $term );
                          echo '<input type="radio" name="prodotto" value="'.$term->slug.'">'.$term->name.'<br>';
                        }       

                    ?>

        </div>
        <input type="button" name="next" class="next btn btn-info" value="Next" />
    </fieldset>
    <fieldset>
        <div class="form-group">
            <h1>2</h1>
            <?php $livello_terms = get_terms( 'livello', array(
          'orderby'    => 'date',
          'order' => 'DESC',
          'hide_empty' => 0
        ) );
    ?>
                <?php foreach( $livello_terms as $term ) {
                          $term_link = get_term_link( $term );
                          echo '<input type="radio" name="livello" value="'.$term->slug.'">'.$term->name.'<br>';
                        }       

                    ?>


                    <?php $ruolo_terms = get_terms( 'ruolo', array(
          'orderby'    => 'date',
          'order' => 'DESC',
          'hide_empty' => 0
        ) );
             ?>
        </div>
        <input type="button" name="previous" class="previous btn btn-default" value="Previous" />
        <input type="button" name="next" class="next btn btn-info" value="Next" />
    </fieldset>
    <fieldset>
        <div class="form-group">
            <h1>3</h1>
            <?php foreach( $ruolo_terms as $term ) {
                          $term_link = get_term_link( $term );
                          echo '<input type="radio" name="ruolo" value="'.$term->slug.'">'.$term->name.'<br>';
                        }       

                    ?>

                            <?php $stato_terms = get_terms( 'stato', array(
          'orderby'    => 'date',
          'order' => 'DESC',
          'hide_empty' => 0
        ) );
            ?>
                    </div>
                    <input type="button" name="previous" class="previous btn btn-default" value="Previous" />
                    <input type="button" name="next" class="next btn btn-info" value="Next" />
                </fieldset>

                <fieldset>
                    <div class="form-group">
                        <h1>4</h1>
                        <?php foreach( $stato_terms as $term ) {
                          $term_link = get_term_link( $term );
                          echo '<input type="radio" name="stato" value="'.$term->slug.'">'.$term->name.'<br>';
                        }       

                    ?>

                    </div>
                    <input type="button" name="previous" class="previous btn btn-default" value="Previous" />
                    <input type="submit" name="submit" class="submit btn btn-success" value="Submit" />
                </fieldset>
            </form>

And this how I tried to output the posts, but nothing is showing up :/

 <?php    
                                if(isset($_REQUEST['submit']))
                                    { 

                                       $prodotto = $_POST["prodotto"];       
                                       $livello = $_POST["livello"];       
                                       $ruolo = $_POST["ruolo"];       
                                       $stato = $_POST["stato"]; 


                                    $soluzioni = new WP_Query( array( 
                                      'post_type' => 'corsi',
                                      'posts_per_page' => -1,
                                      'orderby' => 'title',
                                      'order'   => 'ASC',
                                      'paged' => $paged,
                                      'tax_query' => array(
                                        'relation' => 'AND',
                                         array(
                                           'taxonomy' => 'prodotto',
                                           'field' => 'slug',
                                           'terms' => $prodotto 
                                         ),
                                         array(
                                           'taxonomy' => 'livello',
                                           'field' => 'slug',
                                           'terms' => $livello
                                         )
                                      ) ) );


                                        if ( $soluzioni->have_posts() ) {
                                            echo '<ul>';
                                            while ( $soluzioni->have_posts() ) {
                                                $soluzioni->the_post();
                                                echo '<li>' . get_the_title() . '</li>';
                                            }
                                            echo '</ul>';

                                            wp_reset_postdata();
                                        } else {
                                            // no posts found
                                        }


                                                        } ?>

What am I doing wrong?

Thanks in advance, have a nice day :)

Lisa

Answer 1

Apparently the problem was in the "AND" relation. Code now seems to work:

 <?php    
     if(isset($_REQUEST['submit']))
                { 
                    $prodotto = $_POST["prodotto"];       
                    $livello = $_POST["livello"];       
                    $ruolo = $_POST["ruolo"];       
                    $stato = $_POST["stato"]; 



                    $args = array( 
                            'post_type' => 'corsi',
                            'posts_per_page' => -1,
                            'orderby' => 'title',
                            'order'   => 'ASC',
                            'tax_query' => array(

                                array(
                                    'taxonomy' => 'prodotto',
                                    'field' => 'slug',
                                    'terms' => $prodotto,
                                         ),
                                array(
                                    'taxonomy' => 'livello',
                                    'field' => 'slug',
                                    'terms' => $livello,
                                         ),
                                 array(
                                    'taxonomy' => 'ruolo',
                                    'field' => 'slug',
                                    'terms' => $ruolo,
                                         ),
                              array(
                                    'taxonomy' => 'stato',
                                    'field' => 'slug',
                                    'terms' => $stato,
                                         ),


                                      ) 
                                    );
                    $soluzioni = new WP_Query($args);

                                if ( $soluzioni->have_posts() ) {
                                        echo '<ul>';
                                            while ( $soluzioni->have_posts() ) {
                                                $soluzioni->the_post();
                                                                    echo '<li>' . get_the_title() . '</li>';
                                                                            }
                                                        echo '</ul>';

                                                            wp_reset_postdata();
                                                                } else 
                                                                    {
                                                                           echo '<br/> OPPALLA no post';
                                                                    }




                             }