title: Update using left join in netezza
body: <p>I need to perform a left join of two tables in netezza during an update. How can i achieve this ? Left join with three tables are working but not with two tables.</p>
  
  <pre><code>UPDATE table_1
  SET c2 = t2.c2
  FROM
      table_1 t1
      LEFT JOIN table_2.t1
      ON t1.c1=t2.c1
      LEFT JOIN table_3 t3
      ON t2.c1=t3.c1
  </code></pre>
  
  <p>this works but </p>
  
  <pre><code>UPDATE table_1
  SET c2 = t2.c2
  FROM table_1 t1
      LEFT JOIN table_2.t1
      ON t1.c1=t2.c1
  </code></pre>
  
  <p>this says like trying to update multiple columns.</p>
  
  <p>Thanks,
  Manirathinam.</p>