title: How to extract non-duplicate values in two tables
body: <p>I have two tables where each one contains columns with numbers. I need to compare columns in both tables and extract the number that does exist in first table, and does not exist in second one. I don't need unique value. </p>
  
  <p>I wrote this query:</p>
  
  <pre><code>SELECT Table1.Numbers, Table1.Name
  FROM Table1, Table2
  WHERE Table1.Numbers != Table2.numbers
  </code></pre>
  
  <p>Since I am working on several million records can someone recommend more efficient query which would provide me with identical results?</p>