title: Rails find records using an array of hashes
body: <p>(Select Query by Pair of fields using an <code>in</code> clause)</p>
  
  <p>I have an array of hashes that looks like this:</p>
  
  <p><code>[ {product_id: 7629, group_id: 4}, {product_id: 8202, group_id: 3} ]</code></p>
  
  <p>What I would like to return are all the records in the <code>Items</code> table that match the pair of fields in the array.</p>
  
  <p>In SQL it would be retrieved like this:</p>
  
  <pre><code>SELECT * 
  FROM items
  WHERE (product_id, group_id) IN (VALUES (7629,4), (8202,3))
  </code></pre>
  
  <p>But I am having trouble doing this with a rails <code>.where</code> clause. Is this even possible?</p>