title: Cross join of two tables
body: <p>I have two tables <code>x</code> and <code>y</code>. I want to join on column <code>b</code> such that I get <code>z</code> in output.</p>
  <pre><code>x:([a:1 2 1 3]; b:`a`a`b`b)
  q) a | b
     -----
     1 | a
     2 | a
     1 | b
     3 | b
  
  y:([b:`a`a`a`b]; c:7 8 9 10)
  q) b |  c
     ------
     a |  7
     a |  8
     a |  9
     b | 10
  </code></pre>
  <p>Desired output:</p>
  <pre><code>q) a |  b |  c
     -----------
     1 |  a |  7
     1 |  a |  8
     1 |  a |  9
     2 |  a |  7
     2 |  a |  8
     2 |  a |  9
     1 |  b | 10
     3 |  b | 10
  </code></pre>
  <p>Is this some sort of cross join?</p>