組，計數和連續圈

Question

我無法解決這個問題（比賽），我需要顯示每個LAP的時間。這是多次表

id | race_id  | car_num | time  | 
+-----+-------------+---------+------------+ 
1  | 8   | 25  | 00:09:05 | 
2  | 8   | 33  | 00:09:35 | 
3  | 8   | 10  | 00:09:55 | 
4  | 8   | 25  | 00:18:15 | 
5  | 8   | 33  | 00:19:05 | 
6  | 8   | 25  | 00:39:45 | 

我嘗試此查詢：

SELECT 
    car_num, COUNT(car_num) as laps, race_id, concat(vlap,'-',time) as times 
FROM 
    (SELECT num_car, concat(time,'-',v1) vlap 
    FROM tiempos) vti 
GROUP BY 
    car_num 

這是必需的輸出：

car_num | laps  | race_id | times          | 
+-----+-------------+---------+------------------------------------------------+ 
25   | 3  | 8  | lap1 00:09:05, lap2 00:18:15, lap3 00:39:45 | 
33   | 2  | 8  | lap1 00:09:35, lap2 00:19:05     | 
10   | 1  | 8  | lap1 00:09:55        | 

我暈，一些想法，請

Answer 1

你可以得到大部分你想要的都是簡單的group_concat()：

select car_num, count(*) as laps, race_id, group_concat(time order by id separator ', ') as times 
from tiempos t 
group by car_num, race_id; 

如果你需要的圈數，你可以得到使用變量：

select car_num, count(*) as laps, race_id, group_concat('lap', rn, ' ', time order by id separator ', ') as times 
from (select t.*, 
      (@rn := if(@t = time, @rn + 1, 
         if(@t := time, 1, 1) 
         ) as rn 
     from tiempos t cross join 
      (select @rn := 0, @t := '') vars 
     order by race_id, car_num, time 
    ) t 
group by car_num, race_id;