title: Presto sql nested array data and columns comparison
body: <p>I’m trying to run a Presto SQL query with the following array data.
  What I’m trying to do is a left join on auctions and bids in order to get the auction values from auctions that have not any bids yet.</p>
  <p>To apply <a href="https://prestodb.io/docs/current/functions/map.html" rel="nofollow noreferrer">map</a> functions the arrays should have the same format. However, in this case the arrays differ.
  Could you please provide any ideas how this can be achieved?</p>
  <p>Auctions Array:</p>
  <pre><code>{auctionUser=user1, 
  auctions=[
  {auction=auction1, initial_value=120, item_description = item1},
  {auction=auction2, initial_value=300, item_description = item2},  
  {auction=auction3, initial_value=500, item_description = item3},  
  {auction=auction4, initial_value=300, item_description = item4},  
  {auction=auction5, initial_value=500, item_description = item5},  
  ], 
  Last_Auction_set_at_timestamp=1640857837627, metadata={type=electronics}
  </code></pre>
  <p>Bids Array:</p>
  <pre><code>[ {auction=auction1, bid_value=300, timestamp=1640857837827},  
  {auction=auction5, bid_value=550, timestamp=1640857837951}, 
  {auction=auction2, bid_value=450, timestamp=1640857837988} ]
  </code></pre>