title: Set table equal to CTE
body: <p>I have a table A, that I regularly want to update from another table B.
  I can create a CTE from B that looks exactly like I want table A to look like, but I can't find the syntax for setting A equal to CTE. What I want is something like this:</p>
  <pre><code>WITH cte AS (
      SELECT *,
          ARRAY_AGG(column_name),
          ...
      FROM B
  )
  UPDATE A
  SET 
      A = cte
  FROM cte
  </code></pre>