title: missing FROM-clause entry for table when trying to update / insert
body: <p>Try to update a table with a new set of values,</p>
  <p>if the values already exist then it should update the fields, if it doesn't then it should insert the fields.</p>
  <pre><code>WITH f AS (
  SELECT 1 as MarketId,  
                              'dros@test.com' as userName, 
                              28 as age, 
                              1 as isPremiumMember, 
                              1 as isSubscribed, 
                              '2021-03-12T17:07:30' as LastModifiedOn
      from members
      ) 
  
  
      
      INSERT INTO members
  (age,isPremiumMember,isSubscribed, lastModifiedOn) 
      VALUES (f.age,f.isPremiumMember,f.isSubscribed,f.lastModifiedOn)
      ON CONFLICT (age,isPremiumMember,isSubscribed,lastModifiedOn)
  DO UPDATE SET age= EXCLUDED.age,isPremiumMember = EXCLUDED.isPremiumMember,isSubscribed= EXCLUDED.isSubscribed,lastModifiedOn= EXCLUDED.lastModifiedOn;
  </code></pre>
  <p>however when I run the query I get this error:</p>
  <pre><code>missing FROM-clause entry for table &quot;f&quot;
  </code></pre>
  <p>trying to write this in plain SQL</p>
  <p>INSERT INTO members
  (age,isPremiumMember,isSubscribed, lastModifiedOn)
  select age,isPremiumMember,isSubscribed,lastModifiedOn from f
  ON CONFLICT (age,isPremiumMember,isSubscribed,lastModifiedOn)
  DO UPDATE SET age= EXCLUDED.age,isPremiumMember = EXCLUDED.isPremiumMember,isSubscribed= EXCLUDED.isSubscribed,lastModifiedOn= EXCLUDED.lastModifiedOn;</p>
  <p>tried adding the unique constraint as select as recommend below. this is my current statement.</p>