Question

我想按周汇总sales.quantity的总和，并显示周数，即使没有销售。

我已经设置了一个带有1-54的星期表，以使用外部联接强制所有周数通过，但它不起作用。它错过了没有销售的几周。

我的查询是：

SELECT Weeks.WeekNum, SUM(sales.quantity) AS sales
FROM Weeks LEFT OUTER JOIN 
     sales ON Weeks.WeekNum = DATEPART(week, sales.transDate)
WHERE (sales.transDate BETWEEN @fromDate AND @toDate)
GROUP BY Weeks.WeekNum

任何帮助都会受到极大的接受......我可能已经做过蠢事了！

Answer 1

where子句WHERE (sales.transDate BETWEEN @fromDate AND @toDate)将删除没有销售的任何周。您可能需要执行子查询来提取事务，然后将其连接到您的周表。

SELECT Weeks.WeekNum, SUM(sales.quantity) AS sales
FROM Weeks LEFT OUTER JOIN 
 (
    SELECT *
    FROM sales 
    WHERE (sales.transDate BETWEEN @fromDate AND @toDate)
 ) sales
    ON Weeks.WeekNum = DATEPART(week, sales.transDate)
GROUP BY Weeks.WeekNum

Answer 2

我更喜欢这种方法而非子选择

SELECT Weeks.WeekNum, SUM(sales.quantity) AS sales
FROM Weeks
LEFT OUTER JOIN  sales ON (Weeks.WeekNum = DATEPART(week, sales.transDate) AND sales.transDate BETWEEN @fromDate AND @toDate)
GROUP BY Weeks.WeekNum

Answer 3

正如@ msmucker0527写的那样摆脱WHERE (sales.transDate BETWEEN @fromDate AND @toDate)。你也可以这样做：

SELECT Weeks.WeekNum, SUM(sales.quantity) AS sales
FROM Weeks W  
     LEFT JOIN sales S ON W.WeekNum = DATEPART(week, S.transDate)
            AND S.transDate BETWEEN @fromDate AND @toDate)
GROUP BY W.WeekNum

此外，此WHERE (sales.transDate BETWEEN @fromDate AND @toDate)保证Index Scan Sales表可以大大减慢您的查询速度。
您最好将列WeekFirstDate datetime和WeekLastDate datetime添加到Weeks表和CREATE NONCLUSTERED INDEX IX_Name ON Sales (TransDate) INCLUDE (quantity)中。在这种情况下，您的查询可以通过以下方式更改：

SELECT Weeks.WeekNum, SUM(sales.quantity) AS sales
FROM Weeks W  
     LEFT JOIN sales S ON S.transDate>=W.WeekFirstDate
                          AND S.transDate<=W.WeekLastDate
                          AND S.transDate BETWEEN @fromDate AND @toDate)
GROUP BY W.WeekNum

Answer 4

试试这个：

SELECT Weeks.WeekNum, SUM(sales.quantity) AS sales
FROM Weeks 
LEFT JOIN sales 
       ON Weeks.WeekNum = DATEPART(week, sales.transDate) and
          sales.transDate BETWEEN @fromDate AND @toDate
WHERE Weeks.WeekNum BETWEEN DATEPART(week, @fromDate) AND 
                            DATEPART(week, @toDate)
GROUP BY Weeks.WeekNum

按周汇总，即使是空行也是如此

4 个答案: