title: sql query for top 10 records
body: <p>Can anyone help me for a simple SQL query?</p>
  
  <p>This is the scenario: i need to find the runners who took part to more competitions. Competitions have been in different cities and different specialities. The following table shows better what i mean:</p>
  
  <p>Runner: John White</p>
  
  <pre><code>        -----------------------------------------
          |  NY  |  Rome |  Madrid |  Los Angeles |
   ------------------------------------------------
   | 100m |  x   |       |   x     |              |
   ------------------------------------------------
   | 200m |      |  x    |         |      x       |
   ------------------------------------------------
   | 400m |      |       |         |              |
   ------------------------------------------------
  </code></pre>
  
  <p>In few words i have a database with the following fields: name, city, spec and i need to find the runner who filled more slots, the runner who participated to more different competitions.
  In the "spec" field data are 100m or 200m or 300m if he took part respectively to each speciality
  In the example the result is John White -> 4</p>
  
  <p>So, how can i make a query to list the 1st ten runners who participated to the major number of competitions? I need a table showing the runner name and the number of competitions he took part.</p>
  
  <p>Thanks in advance for your help. If you need more infos just ask.</p>
  
  <p>Bye, Mat</p>
  
  <p>UPDATE: In few words i'd like to know the top 10 list of names that have the maximum number of different combinations of city-specs fields. This one i think is the best logical way to explain my answer.</p>
  
  <p>Here is an example of the database:</p>
  
  <pre><code>name     city      spec
  -----------------------
  john     NY         100m
  john     Rome       200m
  john     Madrid     100m
  john     Los Ang    200m
  mike     Rome       200m
  mike     Rome       100m
  </code></pre>
  
  <p>The "top 10 list" i'm looking for will be the following:</p>
  
  <pre><code>john   4
  mike   2
  </code></pre>
  
  <p>I hope that now it is all ok. Bye!</p>