Here's an example of one that helped me a lot. This takes no time at all to get ChatGPT to generate by giving it anonymized snippets of table data saying:

"here's an example of the relevant tables, I want output that looks like this, what query does that?"

and it just works instantly.

ChatGPT did NOT format it this way, I changed the line breaks and indentation formatting to better fit viewing in Chrome/Safari. I also renamed tables/columns out of personal responsibility, to generic names which make it all the more confusing.

  -- Existing Records
  WITH search_table_A AS (
    SELECT * FROM tableA
    WHERE some_primary_key = :searchKey
  ),
  search_table_B AS (
    SELECT * FROM tableB
    WHERE some_primary_key = :searchKey
  ),
  combined_query AS (
    SELECT COALESCE(search_table_A.our_UUID, search_table_B.our_UUID) AS our_UUID
    FROM search_table_A
    LEFT JOIN search_table_B ON search_table_A.some_primary_key = search_table_B.some_primary_key
  )
  SELECT tableC.* 
  FROM tableC
  JOIN combined_query ON tableC.our_UUID = combined_query.our_UUID;