title: Alternative to NOT EXISTS
body: <p>I have two tables linked by an ID column. Let's call them Table A and table B. My goal is to find all the records in table A that have no record in table B. For instance:  </p>
  
  <pre><code>**Table A:**  
  ID    Value  
  --    -------
  1     value1  
  2     value2  
  3     value3  
  4     value4
  
  **Table B**  
  ID    Value  
  --    -------
  1     x  
  2     y  
  4     z  
  4     l
  </code></pre>
  
  <p>As you can see, record with ID = 3 does not exist in table B, so I want a query that will give me record 3 from table A. The way I am currently doing this is by saying <code>AND NOT EXISTS (SELECT ID FROM TableB where TableB.ID = TableA.ID)</code>, but since the tables are huge, the performance on this is terrible. Also, when I tried using a Left Join where TableB.ID is null, it didn't work. Can anyone suggest an alternative?</p>