title: JOIN - Returns 5 instead of 3 rows for repeating values in ID column
body: <p>I have the following two tables:</p>
  <p>Table A:</p>
  <pre><code>id|valA
  --+----
  1 | a
  2 | b
  2 | c
  </code></pre>
  <p>Table B:</p>
  <pre><code>id|valA
  --+----
  1 | A
  2 | B
  2 | C
  </code></pre>
  <p>What I expect to get using join is:</p>
  <pre><code>id|valA|valB
  --+----+----
  1 | a  | A
  2 | b  | B
  2 | c  | C
  </code></pre>
  <p>However, I get the following</p>
  <pre><code>id|valA|valB
  --+----+----
  1 | a  | A
  2 | b  | B
  2 | c  | B
  2 | c  | C
  2 | b  | C
  </code></pre>
  <p>I am using the following query:</p>
  <pre><code>select id, valA, valB from A
  inner join B
  on A.id = B.id;
  </code></pre>
  <p>How do I use the join to get the expected results?
  What am I doing wrong?</p>