SQL - 获取的最后7天

我有一个表，看起来像这样的平均价格：SQL - 获取的最后7天

timestamp | commodity | amount | price |

我试图得到一个商品的加权平均，每天从过去的7天（为了创建一个图形，C＃程序），我成功地创建一个查询来获取的加权平均值：

SELECT SUM(price * amount), 
     SUM(amount) 
    FROM [table_name] 
WHERE (commodity = @commodity) 
    AND (timestamp >= @fromDate 
    AND timestamp <= @toDate);

所以，我7次，每次加（-1）发送这个查询没有fromdate和toDate，得到最近7天的平均值。

我想问一下在1查询中是否有办法做到这一点，如果有，是否可以实现获取上个月的相同信息。

来源

2017-06-20 Shahaf Nahmias

您可以使用数据透视表。检查[这里]（https://www.techonthenet.com/sql_server/pivot.php） – Badiparmagi

请添加样本数据和预期结果 –

您可以使用转换为日期，但代码如下：

SELECT convert(date, timestamp) as [Dates], 
     SUM(price * amount), 
     SUM(amount) 
    FROM [table_name] 
    WHERE (commodity = @commodity) 
    AND (timestamp >= @fromDate 
    AND timestamp <= @toDate) 
GROUP BY convert(date, timestamp)

来源

2017-06-20 10:33:10

谢谢！有没有办法为没有记录的日期设置默认值？ –

要生成日期，我在下面添加了另一个答案 –

，你必须按日期

SELECT SUM(price* amount),SUM(amount) FROM [table_name] WHERE (commodity = @commodity) AND (cast(timestamp as date)>= @fromDate AND cast(timestamp as date)<= @toDate) 
Group By cast(timestamp as date)

来源

2017-06-20 10:31:48

你应该将你的数据按日期：

SELECT SUM(price * amount),SUM(amount) 
FROM [table_name] 
WHERE (commodity = @commodity) 
AND (timestamp >= @fromDate 
AND timestamp <= @toDate) 
GROUP BY CAST(timestamp as DATE);

来源

2017-06-20 10:46:04

要生成日期，您可以使用如下：

;with Datescte as (
     Select top (datediff(day, @fromDate, @toDate) +1) Dt = Dateadd(day, Row_Number() over (order by (Select null))-1, @fromDate) 
     from master..spt_values s1, master..spt_values s2 
    ), cte2 as (
     SELECT convert(date, timestamp) as [Dates], 
      SUM(price * amount) as [Sum_Price_Amount], 
      SUM(amount) as [Sum_Amount] 
     FROM [table_name] 
     WHERE (commodity = @commodity) 
     AND (timestamp >= @fromDate 
     AND timestamp <= @toDate) 
    GROUP BY convert(date, timestamp) 
    ) 
     Select Dt as [Dates] , Sum_Price_Amount, Sum_Amount 
     FROM Datescte d 
     LEFT JOIN cte2 d2 
      ON d.Dt = d2.Dates

来源

2017-06-20 12:52:11

SQL - 获取的最后7天

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