title: When using Group By in PowerBI desktop Column value is not active
body: <p>In my data set, each <code>PolicyNumber</code> can have multiple <code>ClaimNumber</code>. So all I want to do is to get Unique <code>PolicyNumber</code> and Count the number of Claims (<code>ClaimNumber</code>) for each <code>PolicyNumber</code>. (Like a pivot table in Excel)</p>
  
  <p>In Power BI I click <code>Edit Query</code>, click <code>Group By</code>, specifying the column I want to group on which is <code>PolicyNumber</code>, giving the name to new column (<code>CountOfClaims</code>), Operation - <code>Count Rows</code>...but I am unable to choose <code>Column</code> value. For some reason its inactive. It works if I need to <code>Sum</code>, but I simply need to count <code>ClaimNumber</code> for each <code>PolicyNumber</code>
  It should be so simple. 
  What am I missing here?</p>
  
  <p><a href="https://i.stack.imgur.com/A4YpJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/A4YpJ.png" alt="enter image description here"></a></p>
  
  <p>This is what I am trying to achieve:</p>
  
  <p><a href="https://i.stack.imgur.com/OSbnl.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/OSbnl.png" alt="enter image description here"></a></p>
  
  <p>Also when I am choosing Group By on a panel, then the query has Exclamation sign. I couldnt find a meaning of it.</p>
  
  <p><a href="https://i.stack.imgur.com/g8D9l.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/g8D9l.png" alt="enter image description here"></a></p>