title: Update or insert with outer join in postgres
body: <p>Is it possible to add a new column to an existing table from another table using <code>insert</code> or <code>update</code> in conjunction with <code>full outer join</code> .</p>
  
  <p>In my main table i am missing some records in one column in the other table i have all those records i want to take the full record set into the maintable table. Something like this;</p>
  
  <pre><code>UPDATE maintable 
  SET all_records= othertable.records
  FROM 
  FULL JOIN othertable on maintable.col = othertable.records;
  </code></pre>
  
  <p>Where maintable.col has same id a othertable.records.</p>
  
  <p>I know i could simply join the tables but i have a lot of comments in the maintable i don't want to have to copy paste back in if possible. As i understand using <code>where</code> is equivalent of a <code>left join</code> so won't show me what i'm missing </p>
  
  <p>EDIT: 
  What i want is effectively a new maintable.col with all the records i can then pare down based on presence of records in other cols from other tables</p>