-- For MySQL

-- Method 1: Query Based

WITH RECURSIVE numbers AS (
  SELECT 20 AS i
  UNION ALL
  SELECT i - 1 FROM numbers WHERE i > 1
)
SELECT REPEAT('*', i) AS stars
FROM numbers;

-- Method 2: Using  stored procedure

CREATE PROCEDURE p()
BEGIN
    DECLARE i INT DEFAULT 20;
    WHILE i >= 1 DO
        SELECT REPEAT('* ', i);
        SET i = i - 1;
    END WHILE;
END##

DELIMITER ;

-- To run the procedure:
CALL p();