title: Redshift left outer join is leaving out nulls
body: <p>As background, I've set up 100's of redshift query's, many much more complex than this and yet I think I must be missing something simple.</p>
  
  <p>I am doing a left outer join between Table 1 and Table 2.  The tables are essentially this:</p>
  
  <pre><code>Table1
  Col1  Col2 Col3
  A     C    E
  A     D    F
  
  Table2
  Col 1 Col2 Col3
  A     C    Z
  </code></pre>
  
  <p>I have no where statements.  My on statement is:</p>
  
  <pre><code>on Table1.Col1 = Table2.Col1 and Table1.Col2 = Table2.Col2
  </code></pre>
  
  <p>My result table is:</p>
  
  <pre><code>ResultTable:
  Col1 Col2 Col3 Col4
  A    C    E    Z
  </code></pre>
  
  <p>I was expecting:</p>
  
  <pre><code>ExpectedTable:
  Col1 Col2 Col3 Col4
  A    C    E    Z
  A    D    F    Null
  </code></pre>
  
  <p>What am I missing?  Thanks.</p>