title: LEFT OUTER join issue in SQL
body: <p>I have code that looks something like this:</p>
  
  <pre><code>select t1.colId, t1.col1, t1.col2, t1.col3, count(t2.colId)
  from table1 t1 left outer join
  
  (select colId from db1.tb90) t2 
  on t1.colId = t2.colId
  group by 1,2,3,4
  </code></pre>
  
  <p>I want to copy all rows from t1, and t2 should join where there is a match.</p>
  
  <p>However, <code>t1.colId</code> can include duplicates and want these duplicates to exist.</p>
  
  <p>My current issue is that the select statement performs a distinct on <code>t1.colId</code> so I get the number of distinct <code>t1.colId</code> as oppose of including duplicates. </p>
  
  <p>Is the issue with <code>on t1.colId = t2.colId</code>?</p>