title: What is the best way to validate if a record exists in two tables?
body: <p>I have a table which I update with new data each month.  Sometimes there is a new Location value that comes in the data.  I have another table that holds all the detailed information about a Location that I need to make sure that the new Location value exists.  What is the best way to do that validation?</p>
  
  <p>The data table name is SCM and the location detail table name is LocationDetail.</p>
  
  <p>The field name from SCM is Location and the field name from LocationDetail is LocationCode.</p>
  
  <p>If the new Location is not in the LocationDetail table, I need to know so I can add it in, so I am looking for a query that will show me all the locations from the SCM table that are not in the LocationDetail table.</p>