title: SQL Count Function By Column
body: <pre><code>CusID   Order
  3001    Hotdog
  3001    Sausage
  3002    Sausage
  3003    Burger
  3003    Hotdog
  3002    Hotdog
  3001    Burger
  </code></pre>
  
  <p>How I will use this count function? </p>
  
  <pre><code>SELECT COUNT(CusID) AS NumOfOrders FROM Orders
  </code></pre>
  
  <p>Desired output</p>
  
  <pre><code>CusID   NumOfOrders
  3001    3
  3002    2
  3003    2
  </code></pre>