For MySQL Platform

DELIMITER $$

CREATE PROCEDURE pattern_print()
BEGIN
    DECLARE i INT DEFAULT 1;
    
    WHILE i<=20 DO
        SELECT IF(i=1, "*", REPEAT("* ", i));
        SET i = i + 1;
    END WHILE;
END $$

DELIMITER ;

CALL pattern_print();

WITH RECURSIVE numbers AS ( SELECT 1 AS n UNION ALL SELECT n+1 FROM numbers WHERE n < 20 ) SELECT REPEAT('* ', n) FROM numbers;

SELECT SUBSTR(S,1,ROWNUM * 2) OP FROM DUAL , (SELECT '* * * * * * * * * * * * * * * * * * * *' S FROM DUAL) CONNECT BY LEVEL <= 20;

In SQL Server

DECLARE @i AS INT = 1
WHILE @i <= 20 AND @i >= 1
BEGIN
  PRINT REPLICATE('* ', @i)
  SET @i = @i + 1
END

select rpad ('* ',level * 2, '* ') from dual connect by level <= 20;