MySql Single Table，最后7天select并包含空行

我在这里search了类似的问题在stackoverflow，但我不明白如何使这项工作，我正在试图做…

所以，我想从数据库中获得最近7天的交易，并获得总销售额，如果某天没有数据，也包括空行。

我到目前为止： http : //sqlfiddle.com/#!2/f4eda/6

这输出：

| PURCHASE_DATE | AMOUNT | |---------------|--------| | 2014-04-25 | 19 | | 2014-04-24 | 38 | | 2014-04-22 | 19 | | 2014-04-19 | 19 | 

我想要的是：

 | PURCHASE_DATE | AMOUNT | |---------------|--------| | 2014-04-25 | 19 | | 2014-04-24 | 38 | | 2014-04-23 | 0 | | 2014-04-22 | 19 | | 2014-04-21 | 0 | | 2014-04-20 | 0 | | 2014-04-19 | 19 | 

任何帮助赞赏:)

Answer 1

简单地把你想要的date和使用left outer join的子查询放在一起：

 select d.thedate, coalesce(SUM(amount), 0) AS amount from (select date('2014-04-25') as thedate union all select date('2014-04-24') union all select date('2014-04-23') union all select date('2014-04-22') union all select date('2014-04-21') union all select date('2014-04-20') union all select date('2014-04-19') ) d left outer join transactions t on t.purchase_date = d.thedate and vendor_id = 0 GROUP BY d.thedate ORDER BY d.thedate DESC; 

Answer 2

这并不容易。 我从这个线程中获得了帮助， 从date范围中生成了几天，并将其与查询结合起来。

所以我们的想法是获得最近7天的date列表，然后将这些date的静态数量0join到您的查询中，然后总结它们。 这可以用于任何date范围，只需要在两个查询中改变它们

 select t1.purchase_date, coalesce(SUM(t1.amount+t2.amount), 0) AS amount from ( select DATE_FORMAT(a.Date,'%Y-%m-%d') as purchase_date, '0' as amount from ( select curdate() - INTERVAL (aa + (10 * ba) + (100 * ca)) DAY as Date from (select 0 as a 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) as a cross join (select 0 as a 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) as b cross join (select 0 as a 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) as c ) a where a.Date BETWEEN NOW() - INTERVAL 7 DAY AND NOW() )t1 left join ( SELECT DATE_FORMAT(purchase_date, '%Y-%m-%d') as purchase_date, coalesce(SUM(amount), 0) AS amount FROM transactions WHERE purchase_date BETWEEN NOW() - INTERVAL 7 DAY AND NOW() AND vendor_id = 0 GROUP BY purchase_date )t2 on t2.purchase_date = t1.purchase_date group by t1.purchase_date order by t1.purchase_date desc 

DEMO

Answer 3

这是过去7天;

 select d.thedate, coalesce(SUM(amount), 0) AS amount from (select DATE(NOW()) as thedate union all select DATE(DATE_SUB( NOW(), INTERVAL 1 DAY)) union all select DATE(DATE_SUB( NOW(), INTERVAL 2 DAY)) union all select DATE(DATE_SUB( NOW(), INTERVAL 3 DAY)) union all select DATE(DATE_SUB( NOW(), INTERVAL 4 DAY)) union all select DATE(DATE_SUB( NOW(), INTERVAL 5 DAY)) union all select DATE(DATE_SUB( NOW(), INTERVAL 6 DAY))) d left outer join transactions t on t.purchase_date = d.thedate and vendor_id = 0 GROUP BY d.thedate ORDER BY d.thedate DESC;