title: WP_Query Woocommerce products that belong in distinct multiple categories only tax_query
body: <p>I'm using <code>WP_Query</code> for Woocommerce products in attempt to query products in a particular category.  This is the syntax that worked for me -</p>
  
  <pre><code>$args = array(
      'posts_per_page' =&gt; -1,
      'product_cat' =&gt; 'category-slug-here',
      'post_type' =&gt; 'product',
      'orderby' =&gt; 'title',
  );
  $the_query = new WP_Query( $args );
  // The Loop
  while ( $the_query-&gt;have_posts() ) {
      $the_query-&gt;the_post();
      echo '' . get_the_title() . '&lt;br /&gt;&lt;br /&gt;';
  }
  wp_reset_postdata();
  </code></pre>
  
  <p>This returns data, but I want to pass an ID, not a category slug, to filter and I want to find products that exist in multiple categories <strong>only</strong>.  </p>
  
  <p>The argument <code>product_cat</code> is not native to <code>WP_Query</code> (at least that I can find), so I'm assuming this is something custom to Woocommerce.  Through their documentation, I haven't been able to find anything that will allow me to filter by category ID, nor use an AND condition for this filtering.</p>
  
  <p>Using <code>cat</code>, the array of <code>tax_query</code>, and <code>category__and</code> have not yielded any results.  Essentially, I would like to query all products that exist in both category ID 102, and 115.  If I have to use slugs, I'm sure there is a way around getting that info based on the ID I have, but I'd like to avoid 2 queries to filter by multiple categories.</p>
  
  <p>Does anyone know how to accomplish this?</p>
  
  <p><strong>UPDATE:</strong> I have learned that separating category slugs by commas in the <code>product_cat</code> argument will produce an "OR" effect, so it will combine distinct products from both, but this is not what I am looking for.  So, for example:</p>
  
  <pre><code> 'product_cat' =&gt; 'category-slug1, category-slug2'
  </code></pre>
  
  <p>will return products from both categories in total, but I am still searching for a way to find distinct products that ONLY belong to both, or multiple, categories. </p>