SQL计数记录，按日期分组并填写缺失日期？

Question

我有以下SQL查询计数订单，并按每个日期（日期）进行分组。

因此，下面的结果：

01/02/2014 = 10 
02/02/2014 = 2 
05/02/2014 = 7 
07/02/2014 = 4 

查询：

SELECT TOP(@NumberOfRecords) DATEADD(dd, 0, DATEDIFF(dd, 0, AddedDate)) AS Date,  COUNT(DISTINCT ID) AS Count 
      FROM OrderSpecs 
      GROUP BY DATEADD(dd, 0, DATEDIFF(dd, 0, AddedDate)) 
      ORDER BY Date DESC 

我的问题是，怎样才能让我的查询填写任何在两者之间缺少的日期，并设置计数值为0？

例期望的结果：

01/02/2014 = 10 
    02/02/2014 = 2 
    03/02/2014 = 0 
    04/02/2014 = 0 
    05/02/2014 = 7 
    06/02/2014 = 0 
    07/02/2014 = 4 

你取出时间阅读本非常感谢。

Answer 1

DECLARE @mindate DATETIME 
DECLARE @maxdate DATETIME 
DECLARE @diff INT 
SELECT @maxdate = MAX(addeddate), @mindate = MIN(addeddate) FROM OrderSpecs 
SET @diff = DATEDIFF(DAY, @mindate,@maxdate) 
;WITH cte(dt,level) 
AS 
(
    SELECT @mindate AS dt, 0 AS level 
    UNION ALL 
    SELECT DATEADD(day,1,cte.dt),level + 1 from cte WHERE level < @diff 
) 
SELECT dt,c FROM cte 
LEFT JOIN 
(
    SELECT DATEADD(dd, 0, DATEDIFF(dd, 0,AddedDate)) AddedDt, COUNT(ID) AS c 
    FROM OrderSpecs 
    GROUP BY DATEADD(dd, 0, DATEDIFF(dd, 0,AddedDate)) 
) tab 
ON cte.dt = tab.AddedDt 
OPTION (MaxRecursion 32767); 

CTE被写入来生成日期范围内的所有日期。通过这个聚合结果集的LEFT JOIN完成。

免责声明：如果日期范围是更多的32767天

Answer 2

你可以沿着这条线做些事情。我没有对它进行彻底的测试，但是原则上，如果你正在组织工会，它会抛出额外的费用。您可能需要对输出做一个为了把它放在正确的顺序

SELECT SS1.Date, Count 
FROM 
( 
DECLARE @mindate Date 
DECLARE @maxdate Date 
WITH DateTable 
AS 
(
    SELECT CAST(@mindate as Date) AS [DATE] 
    UNION ALL 
    SELECT DATEADD(dd, 1, [DATE]) FROM DateTable 
    WHERE DATEADD(dd, 1, [DATE]) BETWEEN @mindate AND @maxdate 
) 
SELECT dt.[DATE], 0 [Count] FROM [DateTable] dt 
UNION ALL 

TOP(@NumberOfRecords) DATEADD(dd, 0, DATEDIFF(dd, 0, AddedDate)) AS Date,   COUNT(DISTINCT ID) AS Count 
     FROM OrderSpecs 
     GROUP BY DATEADD(dd, 0, DATEDIFF(dd, 0, AddedDate)) 
     ORDER BY Date DESC 
) SS1 
ORDER BY [Date] 

难道你知道你可以传递作为种子日期开始和结束日期？

Answer 3

如果发出了很多这样的疑问，那么你可以创建一个包含所有日历日期

CREATE TABLE calendar([date] DATE NOT NULL PRIMARY KEY); 

日历表，然后使用外连接

SELECT TOP(@NumberOfRecords) 
     c.Date, COALESCE(o.Count, 0) Count 
    FROM Calendar c LEFT JOIN 
(
    SELECT DATEADD(dd, 0, DATEDIFF(dd, 0, AddedDate)) AS Date, 
     COUNT(DISTINCT ID) AS Count 
    FROM OrderSpecs 
    GROUP BY DATEADD(dd, 0, DATEDIFF(dd, 0, AddedDate)) 
) o 
    ON c.Date = o.Date 
ORDER BY Date DESC 

输出：

 
|  DATE | COUNT | 
|------------|-------| 
| 2014-02-07 |  4 | 
| 2014-02-06 |  0 | 
| 2014-02-05 |  7 | 
| 2014-02-04 |  0 | 
| 2014-02-03 |  0 | 
| 2014-02-02 |  2 | 
| 2014-02-01 | 10 | 

这里是SQLFiddle d emo