SQL group by day, show orders for each day

问题:

I have an SQL 2005 table, let's call it Orders, in the format:

OrderID, OrderDate,  OrderAmount 1,       25/11/2008, 10 2,       25/11/2008, 2 3,       30/1002008, 5 

Then I need to produce a report table showing the ordered amount on each day in the last 7 days:

Day,        OrderCount, OrderAmount 25/11/2008, 2,          12 26/11/2008, 0,          0  27/11/2008, 0,          0  28/11/2008, 0,          0 29/11/2008, 0,          0 30/11/2008, 1,          5 

The SQL query that would normally produce this:

select count(*), sum(OrderAmount)     from Orders     where OrderDate>getdate()-7     group by datepart(day,OrderDate) 

Has a problem in that it will skip the days where there are no orders:

Day,        OrderCount, OrderAmount 25/11/2008, 2,          12 30/11/2008, 1,          5 

Normally I would fix this using a tally table and outer join against rows there, but I'm really looking for a simpler or more efficient solution for this. It seems like such a common requirement for a report query that some elegant solution should be available for this already.

So: 1. Can this result be obtain from a simple query without using tally tables?

and 2. If no, can we create this tally table (reliably) on the fly (I can create a tally table using CTE but recursion stack limits me to 100 rows)?

回答1:

SQL isn't "skipping" dates... because queries run against data that is actually in the table. So, if you don't have a DATE in the table for January 14th, then why would SQL show you a result :)

What you need to do is make a temp table, and JOIN to it.

CREATE TABLE #MyDates ( TargetDate DATETIME ) INSERT INTO #MyDates VALUES CONVERT(DATETIME, CONVERT(VARCHAR, GETDATE() - 0, 101)) INSERT INTO #MyDates VALUES CONVERT(DATETIME, CONVERT(VARCHAR, GETDATE() - 1, 101)) INSERT INTO #MyDates VALUES CONVERT(DATETIME, CONVERT(VARCHAR, GETDATE() - 2, 101)) INSERT INTO #MyDates VALUES CONVERT(DATETIME, CONVERT(VARCHAR, GETDATE() - 3, 101)) INSERT INTO #MyDates VALUES CONVERT(DATETIME, CONVERT(VARCHAR, GETDATE() - 4, 101)) INSERT INTO #MyDates VALUES CONVERT(DATETIME, CONVERT(VARCHAR, GETDATE() - 5, 101)) INSERT INTO #MyDates VALUES CONVERT(DATETIME, CONVERT(VARCHAR, GETDATE() - 6, 101)) INSERT INTO #MyDates VALUES CONVERT(DATETIME, CONVERT(VARCHAR, GETDATE() - 7, 101))  SELECT CONVERT(VARCHAR, TargetDate, 101) AS Date, COUNT(*) AS OrderCount FROM dbo.Orders INNER JOIN #MyDates ON Orders.Date = #MyDates.TargetDate GROUP BY blah blah blah (you know the rest) 

There you go!

回答2:

I had the same problem and this is how I solved it:

SELECT datename(DW,nDays) TimelineDays,      Convert(varchar(10), nDays, 101) TimelineDate,     ISNULL(SUM(Counter),0) Totals  FROM (Select GETDATE() AS nDays     union Select GETDATE()-1     union Select GETDATE()-2     union Select GETDATE()-3     union Select GETDATE()-4     union Select GETDATE()-5     union Select GETDATE()-6) AS tDays  Left Join (Select * From tHistory Where Account = 1000) AS History             on (DATEPART(year,nDays) + DATEPART(MONTH,nDays) + DATEPART(day,nDays)) =              (DATEPART(year,RecordDate) + DATEPART(MONTH,RecordDate) + DATEPART(day,RecordDate))  GROUP BY nDays ORDER BY nDays DESC 

The ouput is:

TimelineDays,   TimelineDate,     Totals  Tuesday         10/26/2010        0 Monday          10/25/2010        6 Sunday          10/24/2010        3 Saturday        10/23/2010        2 Friday          10/22/2010        0 Thursday        10/21/2010        0 Wednesday       10/20/2010        0 

回答3:

If you want to see value zero than put the following query:

select count(*), sum(OrderAmount) from Orders where OrderDate>getdate()-7   and sum(OrderAmount) > 0 or sum(OrderAmount) = 0 group by datepart(day,OrderDate) 

回答4:

Depending on how SQL Server handles temporary tables, you can more or less easily arrange to create a temporary table and populate it with the 7 (or was that 8?) dates you are interested in. You can then use that as your tally table. There isn't a cleaner way that I know of; you can only select data that exists in a table or that can be derived from data that exists in a table or set of tables. If there are dates not represented in the Orders table, you can't select those dates from the Orders table.

回答5:

Since you will want to use this date table frequently in other queries as well, I suggest you make it a permanent table and create a job to add the new year's dates once a year.

回答6:

CREATE PROCEDURE [dbo].[sp_Myforeach_Date]     -- Add the parameters for the stored procedure here     @SatrtDate as DateTime,     @EndDate as dateTime,     @DatePart as varchar(2),     @OutPutFormat as int  AS BEGIN     -- SET NOCOUNT ON added to prevent extra result sets from     -- interfering with SELECT statements.     Declare @DateList Table     (Date varchar(50))      WHILE @SatrtDate

Just put this Code and call the SP in This way

exec sp_Myforeach_Date @SatrtDate='03 Jan 2010',@EndDate='03 Mar 2010',@DatePart='dd',@OutPutFormat=106 

Thanks *Suvabrata Roy ICRA Online Ltd. Kolkata*

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