Question

我试图获得某个特定项目在特定月份内的观看次数。

我有一个看起来像这样的表：

id_component viewed_date
1 | 2013-03-25 11:40:04
3 | 2013-03-26 11:41:04
4 | 2013-04-05 11:42:04
2 | 2013-04-07 11:43:04
3 | 2013-04-12 11:44:04
4 | 2013-04-17 11:45:04
3 | 2013-04-18 11:46:04
2 | 2013-04-20 11:47:04
4 | 2013-04-22 11:48:04

我有一个像这样的组件表：

id, component_name, component_desc, component_price, folder_id
1 | muffler | ford focus muffler | 99.00 | 3
2 | air filter| ford focus air filter | 12.00 | 3
3 | oil filter| ford focus oil filter | 6.00 | 3
4 | wiper | ford focus rear wiper | 6.00 | 3

我目前的疑问是：

SELECT MONTHNAME(viewed_date) AS vmonth, YEAR(viewed_date) AS vyear, COUNT(*) AS vcount  
FROM viewed AS V
RIGHT JOIN components AS C on V.id_component = C.id 
WHERE id_component IN (SELECT id FROM components WHERE folder_id = '3')
GROUP BY YEAR(V.viewed_date), MONTH(V.viewed_date)
ORDER BY V.viewed_date

我想要回来的是：

vmonth = march, vyear = 2012, vcount = 1, id = 1, component_name = muffler, etc. etc.
vmonth = april, vyear = 2012, vcount = 1, id = 2, component_name = air filter, etc. etc.
vmonth = march, vyear = 2012, vcount = 1, id = 3, component_name = oil filter, etc. etc.
vmonth = april, vyear = 2012, vcount = 2, id = 3, component_name = oil filter, etc. etc.
vmonth = april, vyear = 2012, vcount = 3, id = 4, component_name = wiper, etc. etc.

我得到了这个

vmonth = march, vyear = 2012, vcount = 4
vmonth = april, vyear = 2012, vcount = 9

我没有获取加入的数据或单个组件的数据...只是文件夹的每月总数

我做的事情是愚蠢的......有什么建议吗？

Answer 1

您只获得两行，因为您按一对（年，月）分组，在您查看的表中只有两个不同的值。您需要将第三列 - id_component添加到组中以获得所需的结果。此外，您似乎不希望每月，年和ID的每个组合都看到0，因此您需要INNER JOIN而不是外部。

此查询应该为您提供所需的输出：

SELECT v.vmonth, v.vyear, v.vcount, c.id, concat( c.component_name, ', etc. etc.' ) AS component_name
FROM components c
JOIN ( SELECT MONTHNAME( viewed_date ) AS vmonth, YEAR( viewed_date ) AS vyear, id_component, count( * ) AS vcount
       FROM viewed
       GROUP BY vmonth, vyear, id_component ) v 
ON v.id_component = c.id

mysql获取给定月份内查看的组件数

1 个答案: