Question

我目前正在尝试获取过去30天的所有订单并返回总数和订单数量。如果一天没有订单，我仍然希望我的结果中有一行（显然有计数和总数== 0）。

有办法做到这一点吗？

有很多问题要求这个，而不需要总是得到30行。但是，我不能对它们发表评论，因为我的声誉太低了。

例如： selecting all orders for last 30 days, and counting how many per day

Answer 1

另一项工作是简单的左连接到分组订单

（用左连接子查询中的表名和列名更改）

select a.Date, pr.orders_count, pr.price
from (
    select curdate() - INTERVAL (a.a + (10 * b.a) + (100 * c.a)) 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
left join (select order_time, count(*) as orders_count, sum(price) as price from orders group by order_time) pr
on a.Date = pr.order_time
where  a.Date >= NOW() - INTERVAL 30 DAY 
order by a.Date desc

Answer 2

您可以使用日历表或日期维度。

select td.db_date, count(o.OrderId) as Orders
from time_dimension td
  left join Orders o
    on date(o.OrderDate) = db_date
where td.db_date >= date(adddate(curdate(), interval -30 day))
  and td.db_date <= date(curdate())
group by td.db_date

MySQl日历表参考

Answer 3

您可以将发布器用于Get a list of dates between two dates

的日期

您可以在订单表中使用outter join。

Answer 4

尝试 -

SELECT dateDuringPeriod, SUM( orderValue ), COUNT( orderID )
FROM
(
    SELECT dateDuringPeriod,
           IFNULL( orderID, 0 ) orderID,
           IFNULL( orderValue, 0 ) orderValue
    FROM
    (
        SELECT DATE_ADD( CURDATE(), INTERVAL singles + tens DAY) dateDuringPeriod
        FROM 
        (
            SELECT 0 singles
            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
        ) singles JOIN 
        (
            SELECT 0 tens
            UNION ALL SELECT -10
            UNION ALL SELECT -20
        ) tens
    ) datesDuringPeriod LEFT JOIN 
    (
        SELECT orderID,
               DATE( orderDate ) orderDate,
               orderValue
        FROM tblOrders
    ) ordersWithoutTimes
ON datesDuringPeriod.dateDuringPeriod = ordersWithoutTimes.orderDate
) tblOrderSummary
GROUP BY dateDuringPeriod
ORDER BY dateDuringPeriod;

我创建了一个包含示例数据的示例表，发现此代码有效。

选择并计算过去30天的所有订单

4 个答案: