Christmas Tree in SQL

christmas_tree.sql

--- original version found on @iavins Tweet: https://x.com/iavins/status/1871914543590289672

WITH RECURSIVE numbers(n) AS (
  SELECT 1
  UNION ALL
  SELECT n + 1 FROM numbers WHERE n < 9
), tree_parts(level, stars, spaces) AS (
  SELECT 
    n,
    REPEAT('*', n * 2 - 1), 
    REPEAT(' ', 20 - n)
  FROM numbers
), trunk(level, stars, spaces) AS (
  SELECT 10, '|||', REPEAT(' ', 18)
  UNION ALL
  SELECT 11, '|||', REPEAT(' ', 18)
)
SELECT level, spaces || stars AS tree FROM tree_parts
UNION ALL
SELECT level, spaces || stars FROM trunk;