title: PostgreSQL using data from 2 tables without a common value, but a boolean
body: <p>I'm new to Postgres and am trying to find a way that if one value in one table reads true, then to give me a another value in another table.</p>
  <p>Here is one table:</p>
  <pre><code>itemid | pictureid1 | pictureid2 | smallpic | medpic | largepic 
  --------+------------+------------+----------+--------+----------
      100 | 1          | 2          | t        | t      | t
      101 | 3          | 4          | t        | t      | t
      102 | 5          | 6          | t        | t      | t
      103 | 7          | 8          | t        | t      | t
      104 | 9          | 10         | t        | t      | t
      105 | 11         | 12         | t        | t      | t
      106 | 13         | 14         | t        | t      | t
      107 | 15         | 16         | t        | t      | t
      108 | 17         | 18         | t        | t      | t
      109 | 19         | 20         | t        | t      | t
  </code></pre>
  <p>And here is the other:</p>
  <pre><code>id |  size  |                size_url                 
  ----+--------+-----------------------------------------
    1 | small  | https://loremflickr.com/54/54?lock=
    2 | medium | https://loremflickr.com/400/400?lock=
    3 | large  | https://loremflickr.com/1000/1000?lock=
  </code></pre>
  <p>I'm trying to get it where if for a particular itemid it says &quot;true&quot; for smallpic, then it gives me the size_url for small in the other table, with the pictureid1 and pictureid2 in the first table.</p>