title: Joining two indentic select queries in order to get different rows in different columns
body: <p>A select-query of mine always returns a table with one column, but multiple rows.
  I now want to modify the query to append a column with exactly the same data in it to the table, and then LIMIT the first row to 1 and the second to 1,2
  (I want to get the "Top X" of some result, each in a different column.)</p>
  
  <p>My current, not working query, looks like this:</p>
  
  <pre><code>SELECT tag1, tag2 FROM
  (
      (SELECT tag1...) AS t1
      JOIN
      (SELECT tag2...) AS t2
  );
  </code></pre>
  
  <p>Unfortunately, the joined column contains the same value in each row:</p>
  
  <pre><code>Top1    Top2
  1234    1234
  4321    1234
  6543    1234
  8765    1234
  </code></pre>
  
  <p>Whereas the result should be this:</p>
  
  <pre><code>Top1    Top2
  1234    1234
  4321    4321
  6543    6543
  8765    8765
  </code></pre>
  
  <p>So that I can select the first value in the Top1 column and the second in the Top2 column. The final result should therefore be:</p>
  
  <pre><code>Top1    Top2
  1234    4321
  </code></pre>
  
  <p>How can I achieve this, and why isn't my query working?</p>