-- ****************************************************************************
-- This is a very rudimentary recursive common table expression (CTE). By 
-- modifying pieces of it, one can get a sense as to how a recursive CTE works.
-- ****************************************************************************
WITH RECURSIVE "t" AS 
	(
		-- The top part of the UNION query sets the structure of the
		-- query.
		SELECT
			1 AS "counter"
			, CHR( 65 ) AS "extra"
			, CHR( 65 ) AS "example"

		-- The second half of the UNION query must include UNION ALL. 
		-- It must include the CTE in the FROM clause. And it MUST have 
		-- some kind of WHERE clause that will terminate the recursion.
		UNION ALL
		SELECT 
			counter + 1 AS "counter"
			, CHR( 65 + counter ) AS "extra"
			, example ||  CHR( 65 + counter ) AS "example"
		FROM t 
		WHERE counter < 4
	)

SELECT 
	counter
	, extra
	, example
FROM t
;