CREATE TABLE `users` (
  `id` INT(11) NOT NULL AUTO_INCREMENT,
  `age` INT(11) NOT NULL DEFAULT '0',
  `num` INT(11) NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`),
  KEY `age` (`age`),
  KEY `num` (`num`)
) ENGINE=InnoDB AUTO_INCREMENT=11112 DEFAULT CHARSET=utf8


DELIMITER $$
DROP PROCEDURE IF EXISTS InsertRand;
CREATE PROCEDURE InsertRand(IN NumRows INT, IN MinVal INT, IN MaxVal INT)
    BEGIN
        DECLARE i INT;
        SET i = 1;
        START TRANSACTION;
        WHILE i <= NumRows DO
            INSERT INTO users VALUES (i, MinVal + CEIL(RAND() * (MaxVal - MinVal)), CEIL(RAND() * 100));
            SET i = i + 1;
        END WHILE;
        COMMIT;
    END$$
DELIMITER ;

CALL InsertRand(11111, 12, 65);


EXPLAIN SELECT * FROM users WHERE age BETWEEN 18 AND 75 ORDER BY num DESC