В чем заключается ошибка текста? dbForge mysql

CREATE DEFINER = 'root'@'localhost'
FUNCTION football.func_4(T_id integer(10))
  RETURNS INT
BEGIN
DECLARE N float;
SELECT AVG(M) INTO N
  FROM (SELECT MIN(goals.Goal_time) AS M
    FROM teams, games, goals
  WHERE (games.Game_id=goals.Game_id
  AND teams.Team_id=games.Team_1_id   
  AND teams.Team_id=T_id) 
  OR (games.Game_id=goals.Game_id
  AND  teams.Team_id=games.Team_2_id 
  AND teams.Team_id=T_id)
  GROUP BY goals.goal_id);
RETURN N;
END

Говорит об ошибке в тексте и не может сохранить