title: INSERT or UPDATE if exists - why do I get 2 rows inserted instead of 1?
body: <p>I would like to have an insert and update if exists operation on my db.</p>
  
  <p>My table has 'A' defined as PRIMARY. </p>
  
  <pre><code>A int
  B VARCHAR 20
  TEST int
  </code></pre>
  
  <p>why does this query returns '2 row(s) inserted' instead of 1?</p>
  
  <pre><code>insert into test1 (A, B, TEST) 
  values(2, "A", 19) 
  on duplicate key update 
  A=values(A), B=values(B), TEST=values(TEST)
  </code></pre>