title: Joining results of two joins
body: <p>I am looking for the best way to create a query that will do the following(Note: This is just an example, I know this example can be written better, my real goal is a much more complex example, but follows a similar structure)</p>
  
  <pre><code>items
         item_id   |   name      | cost
  
         1         |   Water     | 1.00
         2         |   Chips     | 1.50
  
  trans_local
  
         local_id           |   item_id   |  date
  
         1                  |   1         | '2018-03-12'
         2                  |   1         | '2018-03-13'
         3                  |   2         | '2018-03-13'         
  
  trans_international
  
         international_id   |   item_id   |  currency | date
  
         1                  |   1         |  'GBP'    | '2018-03-11'
         2                  |   2         |  'EUR'    | '2018-03-12'
         3                  |   2         |  'GBP'    | '2018-03-12'
  </code></pre>
  
  <p>I'm looking to create a select statement a table that lists all transactions in it.   </p>
  
  <pre><code> local_id   | international_id |  item_id | item_name | item_cost | currency | date
  
   1          | null             |  1       | Water     | 1.00      | null     | '2018-03-12'
   2          | null             |  1       | Water     | 1.00      | null     | '2018-03-13'
   3          | null             |  2       | Chips     | 1.50      | null     | '2018-03-13'
   null       | 1                |  1       | Water     | 1.00      | 'GBP'    | '2018-03-11'
   null       | 2                |  2       | Chips     | 1.50      | 'EUR'    | '2018-03-12'
   null       | 3                |  2       | Chips     | 1.50      | 'GBP'    | '2018-03-12'
  </code></pre>
  
  <p><code>items</code> should be joined to either <code>trans_local</code> or <code>trans_international</code>.  I know I can do this with <code>LEFT OUTER JOIN</code>,  but I am unsure how to get results of all transactions together.  I believe it would be a <code>FULL JOIN</code> but getting everything together is confusing me a bit.  Any help would be greatly appreciated. </p>