title: I need to find out which SQL columns do not match
body: <p>OK this seems to be a little complicated and confusing.</p>
  
  <p>I have a base table </p>
  
  <pre><code>Schedule
  (
      RowID, 
      ScheduleName, 
      ScheduleColumn1, 
      ScheduleColumn2, 
      ScheduleColumn3
  )
  </code></pre>
  
  <p>I have a separate application that imports records to another table  </p>
  
  <pre><code>ImportSchedule
  (
      RowID, 
      ScheduleName,
      ScheduleColumn1, 
      ScheduleColumn2,  
      ScheduleColumn3 
  )
  </code></pre>
  
  <p>Now I need to join the 2 tables and display records that do no match. Basically if table <code>ImportSchedules</code> does not have matching records on columns <code>ScheduleColumn1</code>, <code>ScheduleColumn2</code>, <code>ScheduleColumn3</code> with table <code>Schedule</code>.</p>
  
  <p>This is easy with the help of left join on all the above three columns. </p>
  
  <p>The difficult part is finding which column does not match and list it as a failure reason.</p>