title: UPDATING a table which is selected using SELECT query in SQL
body: <p>I want to use the <code>Update</code> keyword with <code>select</code> something like </p>
  
  <pre><code>UPDATE(select col1,col2,col3 from UNPIVOTED_TABLE)
  SET col1=0
  WHERE col1 IS NULL
  SET col2=0
  WHERE col2 is NULL
  SET col3=0
  WHERE col3 is NULL
  </code></pre>
  
  <p>I know my syntax is not right but this basically is what i am trying to achieve</p>
  
  <p>I am selecting 3 columns and there are some <code>null</code> values which i want to update and set it as 0</p>
  
  <p>Also i cannot update the table itself since the original table was <code>UNPIVOTED</code> and i am <code>PIVOTING</code> it in the select statement and i need the pivoted result (that is the columns i have selected) (col1,col2,col3)</p>
  
  <p>Also i am using amazon Athena if that is relevant </p>