title: How do I query taxonomy OR custom field in Wordpress at the same time?
body: <p>I need to query wordpress posts returning results that could be matched either by the category OR custom field. Using the below code only returns results if they are matched by the category AND custom field. I need to find matches where it could be matched by either query, so an "OR" result but doesn't seem to work.</p>
  
  <p>Can anyone help?</p>
  
  <pre><code>$args =  array(
  'post_type' =&gt; 'post',
  'tax_query' =&gt; array(
  'relation' =&gt; 'OR',
      array(
          'taxonomy'  =&gt; 'category',
          'field'     =&gt; 'slug',
          'terms' =&gt; array( 'arts','food' ),
          'operator'  =&gt; 'IN'
      )
  ),
  'meta_query' =&gt; array(
     'relation' =&gt; 'OR',
      array(
          'key' =&gt; 'birth_city',
          'value' =&gt; 'London',
          'compare' =&gt; 'IN',
        ),
     )
  );
  </code></pre>