title: Count of distinct records - SQL
body: <pre><code>empid   projectId   TaskID
  100     500           1
  100     501           1
  100     502           1
  101     500           2
  101     500          5
  101     500          1
  102     400          1
  103     300          2
  104     300          2
  105     300          2  
  </code></pre>
  
  <p>I am trying to list the employees who works on multiple project only,  based on project id .
  I tried distinct and GROUP BY . but am not able figure it exactly.</p>
  
  <p>from the above table am expecting a result like this</p>
  
  <pre><code> empid   projectId  
      100     500         
      100     501          
      100     502 
  </code></pre>