13. Solutions: UNION

Quiz 1:

SELECT *
    FROM accounts

UNION ALL

SELECT *
  FROM accounts

Quiz 2:

SELECT *
    FROM accounts
    WHERE name = 'Walmart'

UNION ALL

SELECT *
  FROM accounts
  WHERE name = 'Disney'

Quiz 3:

WITH double_accounts AS (
    SELECT *
      FROM accounts

    UNION ALL

    SELECT *
      FROM accounts
)

SELECT name,
       COUNT(*) AS name_count
 FROM double_accounts 
GROUP BY 1
ORDER BY 2 DESC