title: IN() returns 'Cardinality violation: 1242 Subquery returns more than 1 row'
body: <p>I want to return all <code>place_id</code>s which meet ANY of the 2 criteria specified by two subqueries. Each of these subqueries can return more than 1 row, because I can have multiple places meeting a subquery's condition. </p>
  
  <pre><code>SELECT p.place_id
  FROM places p
  LEFT JOIN rel_place_custom_fields rpcf ON p.place_id = rpcf.place_id 
  WHERE rpcf.place_id IN 
      ((SELECT rpcf.place_id FROM rel_place_custom_fields rpcf
        WHERE rpcf.field_id = 29 AND rpcf.field_value = :value_29_0), 
       (SELECT rpcf.place_id FROM rel_place_custom_fields rpcf
        WHERE rpcf.field_id = 29 AND rpcf.field_value = :value_29_1)) 
  GROUP BY place_id
  </code></pre>
  
  <p>It returns the following error:</p>
  
  <blockquote>
    <p>Uncaught exception: SQLSTATE[21000]: Cardinality violation: 1242
    Subquery returns more than 1 row</p>
  </blockquote>
  
  <p>What is the better way to do it? I was told that it can be done with <code>JOIN</code>, but have no idea how to do it myself.</p>