MySQL Group By Hours

Question

Estoy tratando de obtener un informe de mi tabla de historial por uso por hora. history tabla es;

CREATE TABLE IF NOT EXISTS `history` (
`history_id` int(11) unsigned NOT NULL AUTO_INCREMENT, 
`user_id` int(11) unsigned NOT NULL DEFAULT '0', 
`created` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, 
PRIMARY KEY (`history_id`), 
KEY `user_id` (`user_id`), 
KEY `created` (`created`) 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=1 ; 

que desea agrupar por HOURCOUNT y todos los registros en un determinado intervalo de fechas.

Hours   | Usage 
------------------------------------ 
00:00-01:00  |  5 
01:00-02:00  |  9 
02:00-03:00  |  0 (or NULL) 
03:00-04:00  |  20 
... 
... 
... 
22:00-23:00  |  11 
23:00-00:00  |  1 

He utilizado una consulta como esta pero no muestra todas las horas.

SELECT 

CASE 
    WHEN HOUR(created) BETWEEN 0 AND 1 THEN '00:00 - 01:00' 
    WHEN HOUR(created) BETWEEN 1 AND 2 THEN '01:00 - 02:00' 
    WHEN HOUR(created) BETWEEN 2 AND 3 THEN '02:00 - 03:00' 
    WHEN HOUR(created) BETWEEN 3 AND 4 THEN '03:00 - 04:00' 
    WHEN HOUR(created) BETWEEN 4 AND 5 THEN '04:00 - 05:00' 
    WHEN HOUR(created) BETWEEN 5 AND 6 THEN '05:00 - 06:00' 
    WHEN HOUR(created) BETWEEN 6 AND 7 THEN '06:00 - 07:00' 
    WHEN HOUR(created) BETWEEN 7 AND 8 THEN '07:00 - 08:00' 
    WHEN HOUR(created) BETWEEN 8 AND 9 THEN '08:00 - 09:00' 
    WHEN HOUR(created) BETWEEN 9 AND 10 THEN '09:00 - 10:00' 
    WHEN HOUR(created) BETWEEN 10 AND 11 THEN '10:00 - 11:00' 
    WHEN HOUR(created) BETWEEN 11 AND 12 THEN '11:00 - 12:00' 
    WHEN HOUR(created) BETWEEN 12 AND 13 THEN '12:00 - 13:00' 
    WHEN HOUR(created) BETWEEN 13 AND 14 THEN '13:00 - 14:00' 
    WHEN HOUR(created) BETWEEN 14 AND 15 THEN '14:00 - 15:00' 
    WHEN HOUR(created) BETWEEN 15 AND 16 THEN '15:00 - 16:00' 
    WHEN HOUR(created) BETWEEN 16 AND 17 THEN '16:00 - 17:00' 
    WHEN HOUR(created) BETWEEN 17 AND 18 THEN '17:00 - 18:00' 
    WHEN HOUR(created) BETWEEN 18 AND 19 THEN '18:00 - 19:00' 
    WHEN HOUR(created) BETWEEN 19 AND 20 THEN '19:00 - 20:00' 
    WHEN HOUR(created) BETWEEN 20 AND 21 THEN '20:00 - 21:00' 
    WHEN HOUR(created) BETWEEN 21 AND 22 THEN '21:00 - 23:00' 
    WHEN HOUR(created) BETWEEN 22 AND 23 THEN '22:00 - 23:00' 
    WHEN HOUR(created) BETWEEN 23 AND 24 THEN '23:00 - 00:00' 
END AS `Hours`, 

COUNT(*) AS `usage` 
FROM history 
WHERE (created BETWEEN '2012-02-07' AND NOW()) 
GROUP BY 
    CASE 
    WHEN HOUR(created) BETWEEN 0 AND 1 THEN 1 
    WHEN HOUR(created) BETWEEN 1 AND 2 THEN 2 
    WHEN HOUR(created) BETWEEN 2 AND 3 THEN 3 
    WHEN HOUR(created) BETWEEN 3 AND 4 THEN 4 
    WHEN HOUR(created) BETWEEN 4 AND 5 THEN 5 
    WHEN HOUR(created) BETWEEN 5 AND 6 THEN 6 
    WHEN HOUR(created) BETWEEN 6 AND 7 THEN 7 
    WHEN HOUR(created) BETWEEN 7 AND 8 THEN 8 
    WHEN HOUR(created) BETWEEN 8 AND 9 THEN 9 
    WHEN HOUR(created) BETWEEN 9 AND 10 THEN 10 
    WHEN HOUR(created) BETWEEN 10 AND 11 THEN 11 
    WHEN HOUR(created) BETWEEN 11 AND 12 THEN 12 
    WHEN HOUR(created) BETWEEN 12 AND 13 THEN 13 
    WHEN HOUR(created) BETWEEN 13 AND 14 THEN 14 
    WHEN HOUR(created) BETWEEN 14 AND 15 THEN 15 
    WHEN HOUR(created) BETWEEN 15 AND 16 THEN 16 
    WHEN HOUR(created) BETWEEN 16 AND 17 THEN 17 
    WHEN HOUR(created) BETWEEN 17 AND 18 THEN 18 
    WHEN HOUR(created) BETWEEN 18 AND 19 THEN 19 
    WHEN HOUR(created) BETWEEN 19 AND 20 THEN 20 
    WHEN HOUR(created) BETWEEN 20 AND 21 THEN 21 
    WHEN HOUR(created) BETWEEN 21 AND 22 THEN 22 
    WHEN HOUR(created) BETWEEN 22 AND 23 THEN 23 
    WHEN HOUR(created) BETWEEN 23 AND 24 THEN 24 
END 

Se visualiza solo si hay registros.

Hours   | Usage 
------------------------------------ 
00:00-01:00  |  5 
01:00-02:00  |  9 
23:00-00:00  |  1 

Answer 1

Su consulta existente puede reducirse a:

SELECT CONCAT(HOUR(created), ':00-', HOUR(created)+1, ':00') AS Hours 
    ,  COUNT(*) AS `usage` 
FROM  history 
WHERE created BETWEEN '2012-02-07' AND NOW() 
GROUP BY HOUR(created) 

Para mostrar cada horas, incluyendo aquellos para los cuales no hay datos, es necesario combinación externa con una tabla que contiene todas las horas para el cual quieres datos Se puede construir una tabla de este tipo en su consulta mediante UNION:

SELECT CONCAT(Hour, ':00-', Hour+1, ':00') AS Hours 
    ,  COUNT(created) AS `usage` 
FROM  history 
    RIGHT JOIN (
        SELECT 0 AS Hour 
     UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 
     UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 
     UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9 
     UNION ALL SELECT 10 UNION ALL SELECT 11 UNION ALL SELECT 12 
     UNION ALL SELECT 13 UNION ALL SELECT 14 UNION ALL SELECT 15 
     UNION ALL SELECT 16 UNION ALL SELECT 17 UNION ALL SELECT 18 
     UNION ALL SELECT 19 UNION ALL SELECT 20 UNION ALL SELECT 21 
     UNION ALL SELECT 22 UNION ALL SELECT 23 
)  AS AllHours ON HOUR(created) = Hour 
WHERE created BETWEEN '2012-02-07' AND NOW() OR created IS NULL 
GROUP BY Hour 
ORDER BY Hour 

Sin embargo, el tratamiento de los grupos para los cuales no existen datos es realmente una cuestión de lógica de negocio que se coloca mejor en su capa de acceso a datos en lugar de en la base de datos sí mismo: de hecho, debería ser trivial para su aplicación usar un valor cero cada vez que falte una hora.

Answer 2

dieron una mesa Log con columnas ts y valor, la siguiente dará el promedio cada hora durante las últimas 24 horas (suponiendo que cada hora tiene al menos una fila).

SELECT 
    FROM_UNIXTIME(TRUNCATE(UNIX_TIMESTAMP(`ts`)/3600, 0) * 3600) as h, 
    AVG(`value`) as v, 
    COUNT(*) as q 
FROM 
    Log 
GROUP BY 
    h 
ORDER BY 
    h desc 
LIMIT 
    24 

La columna ts puede ser una columna de marca de hora o fecha y hora mientras valor es cualquier cosa que AVG() aceptará.