我有一个工作表,正在尝试获取不同时间范围内的工作数.我当前的查询如下所示：
SELECT COUNT(*) AS 'count',WEEK(j.created_at) AS 'week',MONTH(j.created_at) AS 'month',YEAR(j.created_at) AS 'year',DATE_FORMAT(j.created_at,'%y') AS 'short_year'
FROM jobs j WHERE j.state <> 'draft'
AND created_at > '2010-06-21'
AND created_at < '2010-08-01'
GROUP BY WEEK(j.created_at)
ORDER BY WEEK(j.created_at)
要更改时间范围,我只需将GROUP BY从WEEK更改为MONTH,就可以按月而不是按周进行计数.
问题是我有0个工作的几周没有空行.我从上面的查询中得到的结果是：
count week month year short_year
3 25 6 2010 10
2 26 6 2010 10
2 27 7 2010 10
1 28 7 2010 10
3 30 7 2010 10
您会注意到第29周没有数据,该数据应该是带有count(0)的行.有什么办法可以使那0计数行,同时保持在WEEK和MONTH之间更改分组的灵活性？
最佳答案
创建一个包含每个日期和该日期的外部联接的辅助日历表(如果created_at具有时间分量,则下面可能需要调整)
SELECT COUNT(*) AS 'count',WEEK(c.date) AS 'week',MONTH(c.date) AS 'month',YEAR(c.date) AS 'year',DATE_FORMAT(c.date,'%y') AS 'short_year'
FROM calendar c
LEFT OUTER JOIN jobs j ON j.created_at = c.date
AND j.state <> 'draft'
WHERE c.date > '2010-06-21'
AND c.date < '2010-08-01'
GROUP BY WEEK(c.date)
ORDER BY WEEK(c.date)