mysql code stackoverflow

DELIMITER //
CREATE PROCEDURE filltable()
BEGIN

    DECLARE n INT DEFAULT 0;
    DECLARE i INT DEFAULT 0;
    DECLARE var1 VARCHAR(40);
    DECLARE var2 VARCHAR(40);

    SELECT COUNT(*) into n FROM mytable;
    SET i=1;
    WHILE i <= n DO
        SELECT name FROM mytable WHERE id=i INTO var1;

        IF var1 IS NOT NULL THEN SET var2 = var1;
        ELSE UPDATE mytable SET name = var2 WHERE id = i;

        SET i = i + 1;
    END WHILE;

END//
DELIMITER ;