title: Bulk updating a table from rows from another table
body: <p>2 tables: </p>
  
  <pre><code>Employees
  - EmployeeID
  - LeadCount
  
  
  Leads
  - leadID
  - employeeID
  </code></pre>
  
  <p>I want to update the <code>Employees.LeadCount</code> column by counting the # of leads in the <code>Leads</code> table that have the same <code>EmployeeID</code>.</p>
  
  <p>Note:  There may be more than 1 lead with the same employeeID, so I have to do a <code>DISTINCT(SUM(employeeID))</code>.</p>