FROM `table` AS `SLAVE`

INSERT INTO `tbl` (`id`, `uid`, `fio`, `age`) VALUES
(1, 1, 'Иванов', 47),
(2, 2, 'Петров', 34),
(3, 3, 'Сидоров', 55),
(4, 2, 'Петров', 35),
(5, 1, 'Иванов', 49),
(6, 1, 'Иванов', 48);

SELECT 
    `uid`, 
    `fio`, 
    `age`, 
    (
        SELECT 
        	COUNT(1) 
        FROM `tbl` AS `slave` 
        WHERE `slave`.`id`<=`main`.`id` AND `slave`.`uid`=`main`.`uid`
    ) AS `q`
FROM 
	`tbl` AS `main`
ORDER BY 
	`uid`,`q`

SELECT 
    `uid`, 
    `fio`, 
    `age`, 
    IF(@uid = `uid`,
       @rownum := @rownum + 1,
       @rownum :=1 + least(0, @uid := `uid`)
    ) AS `q`
FROM 
	`tbl`,
    (SELECT @rownum := 1, @uid := '_') AS `z`
ORDER BY 
	`uid`,`age`

1 	Иванов 	47 	1
1 	Иванов 	48 	2
1 	Иванов 	49 	3
2 	Петров 	34 	1
2 	Петров 	35 	2
3 	Сидоров 	55 	1

SELECT `SLAVE`.`fio`, `SLAVE`.age, COUNT(`SLAVE`.`fio`)
FROM tbl AS MAIN
   LEFT JOIN tbl AS `SLAVE` ON `SLAVE`.`uid`=MAIN.`uid` AND `SLAVE`.id>=MAIN.id
GROUP BY `SLAVE`.`uid`, `SLAVE`.price