MySQL divide calculation from two tables - mysql

Question

for my page I have to divide values ​​from two tables.
I get the first value of the calculation from table one (game), where two values ​​are added to one. From table two (game_stats) I get the second value of the invoice. The values ​​Rounds and Kills should now be divided and saved or updated in the table game_stats_more as a value.
My current problem is that when I calculate the values ​​I get an error that the AS values ​​are not recognized. Where did I get my Select error?
SELECT SUM(game.match_score_team_1 + game.match_score_team_2) AS Rounds, game_stats.match_stats_kills AS Kills, Rounds / Kills AS KPR FROM game INNER JOIN game_stats WHERE game.match_id = 1 AND game_stats.user_id = 1
Error Message:
#1054 - Unknown table field 'Rounds' in field list
Sample schema:
CREATE TABLE `game` (
`match_id` int(3) NOT NULL,
`team_id` int(3) NOT NULL,
`match_team_2` varchar(255) COLLATE utf8_german2_ci NOT NULL,
`match_score_team_1` int(2) NOT NULL,
`match_score_team_2` int(2) NOT NULL,
`match_score_role_id` int(3) NOT NULL,
`match_role_id` int(3) NOT NULL,
`date` date NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_german2_ci;
INSERT INTO `game` (`match_id`, `team_id`, `match_team_2`, `match_score_team_1`, `match_score_team_2`, `match_score_role_id`, `match_role_id`, `date`) VALUES
(1, 7, 'TestGegner', 7, 2, 1, 1, '2020-06-10'),
CREATE TABLE `game_stats` (
`match_stats_id` int(3) NOT NULL,
`match_id` int(3) NOT NULL,
`user_id` int(3) NOT NULL,
`match_stats_kills` int(2) NOT NULL,
`match_stats_deaths` int(2) NOT NULL,
`match_stats_entry_kill` int(2) NOT NULL,
`match_stats_entry_death` int(2) NOT NULL,
`match_stats_clutch` int(2) NOT NULL,
`match_stats_plants` int(2) NOT NULL,
`match_stats_hs` int(2) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_german2_ci;
INSERT INTO `game_stats` (`match_stats_id`, `match_id`, `user_id`, `match_stats_kills`, `match_stats_deaths`, `match_stats_entry_kill`, `match_stats_entry_death`, `match_stats_clutch`, `match_stats_plants`, `match_stats_hs`) VALUES
(1, 1, 1, 7, 5, 1, 3, 1, 4, 4),
(2, 1, 2, 6, 6, 2, 2, 0, 1, 3);
CREATE TABLE `game_stats_more` (
`game_stats_id` int(3) NOT NULL,
`game_id` int(3) NOT NULL,
`game_stats_more_kpr` int(3) NOT NULL,
`game_stats_more_hsp` int(3) NOT NULL,
`game_stats_more_kd` int(3) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_german2_ci;
INSERT INTO `game_stats_more` (`game_stats_id`, `game_id`, `game_stats_more_kpr`, `game_stats_more_hsp`, `game_stats_more_kd`) VALUES
(1, 1, 0, 0, 0);

Answer 1

You cannot use alias defined for field in same select statement
SELECT (game.match_score_team_1 + game.match_score_team_2) AS Rounds,
game_stats.match_stats_kills AS Kills,
(game.match_score_team_1 + game.match_score_team_2) /
game_stats.match_stats_kills AS KPR
FROM game
INNER JOIN game_stats ON game.match_id=game_stats.match_id
WHERE game.match_id = 1 AND game_stats.user_id = 1