title: Full Outer Join on Access
body: <p>I need to perform a FULL OUTER JOIN in Access, so I found a thread on Stack Overflow that gave me the following model: </p>
  
  <pre><code>SELECT *
      FROM AA
          LEFT JOIN BB ON AA.C_ID = BB.C_ID AND AA.Currency = BB.Currency
  UNION
  SELECT *
      FROM AA
          RIGHT JOIN BB ON AA.C_ID = BB.C_ID AND AA.Curency = BB.Currency
  </code></pre>
  
  <p>So at first it seems to work (around 95% of the results match) but when I check the total sum of a column, it has slightly changed (In my case I have 800K rows, therefore the change is quite important).</p>
  
  <p>Also, some of the IDs in each table are NULL, and each row with an ID NULL needs to be on a different row after the full outer join .
  I think that some rows, do you know what's wrong ? </p>
  
  <p>Thanks in advance</p>