title: Get the latest 3 nodes foreach taxonomy term in one query
body: <p>I am trying to setup a query to get the 3 most recent nodes (nid) foreach taxonomy term (tid).  Is this possible to set up on one query?</p>
  
  <p>Here are how my tables are set up (not displaying full table info)</p>
  
  <p><strong>taxonomy_index</strong> (Holds the taxonomy ids that are associated to a node)</p>
  
  <pre><code>nid      tid
  1         20
  1         21
  1         22
  2         20
  2         21
  3         23
  3         24
  4         20
  4         21
  5         20
  5         21
  5         22
  5         23
  6         20
  6         21
  6         24
  7         20
  7         21
  8         20
  8         21
  9         20
  9         21
  9         22
  9         23
  .....
  </code></pre>
  
  <p><strong>node</strong> (node information)</p>
  
  <pre><code>nid    title           created
  1      Article One     1105350260
  2      Article Two     1105350259
  3      Article Three   1105350261
  4      Article Four    1105350280
  5      Article Five    1105350290
  6      Article Six     1105350290
  .....
  </code></pre>
  
  <p>I'm envisioning a result like this if I wanted to see the latest 3 nodes for tids: 20, 21, 22:</p>
  
  <pre><code>tid     nid
  20       1
  20       2
  20       4
  21       1
  21       2
  21       4
  22       1
  22       5
  22       9
  </code></pre>
  
  <p>Is this possible in one query?</p>