SQL Query issue with joining data don't exist in table [duplicate] - mysql

Question

I've got a SQL Server CE 3.5 table (Transactions) with the following Schema:
ID
Transaction_Date
Category
Description
Amount
Query:
SELECT Transaction_Date, SUM(Amount)
FROM Transactions
GROUP BY Transaction_Date;
I'm trying to do a SUM(Amount) and group by transaction_date just so I can get the total amount for each day but I want to get back values even for days there were no transactions so basically the record for a day with no transactions would just have $0.00 for amount.
Thanks for the help!

Answer 1

You need a Calendar table to select over the dates. Alternatively, if you have a Numbers table, you could turn that effectively into a Calendar table. Basically, it's just a table with every date in it. It's easy enough to build and generate the data for it and it comes in very handy for these situations. Then you would simply use:
SELECT
C.calendar_date,
SUM(T.amount)
FROM
Calendar C
LEFT OUTER JOIN Transactions T ON
T.transaction_date = C.calendar_date
GROUP BY
C.calendar_date
ORDER BY
C.calendar_date
A few things to keep in mind:
If you're sending this to a front-end or reporting engine then you should just send the dates that you have (your original query) and have the front end fill in the $0.00 days itself if that's possible.
Also, I've assumed here that the date is an exact date value with no time component (hence the "=" in the join). Your calendar table could include a "start_time" and "end_time" so that you can use BETWEEN for working with dates that include a time portion. That saves you from having to strip off time portions and potentially ruining index usage. You could also just calculate the start and end points of the day when you use it, but since it's a prefilled work table it's easier IMO to include a start_time and end_time.

Answer 2

You'll need to upper and lower bound your statement somehow, but perhaps this will help.
DECLARE #Start smalldatetime, #End smalldatetime
SELECT #Start = 'Jan 1 2010', #End = 'Jan 18 2010';
--- make a CTE of range of dates we're interested in
WITH Cal AS (
SELECT CalDate = convert(datetime, #Start)
UNION ALL
SELECT CalDate = dateadd(d,1,convert(datetime, CalDate)) FROM Cal WHERE CalDate < #End
)
SELECT CalDate AS TransactionDate, ISNULL(SUM(Amount),0) AS TransactionAmount
FROM Cal AS C
LEFT JOIN Transactions AS T On C.CalDate = T.Transaction_Date
GROUP BY CalDate ;

Answer 3

Once you have a Calendar table (more on that later) you can then do an inner join on the range of your data to fill in missing dates:
SELECT CalendarDate, NULLIF(SUM(t.Amount),0)
FROM (SELECT CalendardDate FROM Calendar
WHERE CalendarDate>= (SELECT MIN(TransactionDate) FROM Transactions) AND
CalendarDate<= (SELECT MAX(TransactionDate) FROM Transactions)) c
LEFT JOIN
Transactions t ON t.TransactionDate=c.CalendarDate
GROUP BY CalendarDate
To create a calendar table, you can use a CTE:
WITH CalendarTable
AS
(
SELECT CAST('20090601' as datetime) AS [date]
UNION ALL
SELECT DATEADD(dd, 1, [date])
FROM CTE_DatesTable
WHERE DATEADD(dd, 1, [date]) <= '20090630' /* last date */
)
SELECT [date] FROM CTE_DatesTable
OPTION (MAXRECURSION 0);
Combining the two, we have
WITH CalendarTable
AS
(
SELECT MIN(TransactionDate) FROM Transactions AS [date]
UNION ALL
SELECT DATEADD(dd, 1, [date])
FROM CTE_DatesTable
WHERE DATEADD(dd, 1, [date]) <= (SELECT MAX(TransactionDate) FROM Transactions)
)
SELECT c.[date], NULLIF(SUM(t.Amount),0)
FROM Calendar c
LEFT JOIN
Transactions t ON t.TransactionDate=c.[date]
GROUP BY c.[date]

Answer 4

Not sure if any this works with CE
With common table expressions
DECLARE #StartDate DATETIME
DECLARE #EndDate DATETIME
SET #StartDate = '2010-07-10'
SET #EndDate = '2010-07-20'
;WITH Dates AS (
SELECT #StartDate AS DateValue
UNION ALL
SELECT DateValue + 1
FROM Dates
WHERE DateValue + 1 <= #EndDate
)
SELECT Dates.DateValue, ISNULL(SUM(Transactions.Amount), 0)
FROM Dates
LEFT JOIN Transactions ON
Dates.DateValue = Transactions.Transaction_Date
GROUP BY Dates.DateValue;
With loop + temporary table
DECLARE #StartDate DATETIME
DECLARE #EndDate DATETIME
SET #StartDate = '2010-07-10'
SET #EndDate = '2010-07-20'
SELECT #StartDate AS DateValue INTO #Dates
WHILE #StartDate <= #EndDate
BEGIN
SET #StartDate = #StartDate + 1
INSERT INTO #Dates VALUES (#StartDate)
END
SELECT Dates.DateValue, ISNULL(SUM(Transactions.Amount), 0)
FROM #Dates AS Dates
LEFT JOIN Transactions ON
Dates.DateValue = Transactions.Transaction_Date
GROUP BY Dates.DateValue;
DROP TABLE #Dates

Answer 5

If you want dates that don't have transactions to appear
you can add a DUMMY transaction for each day with the amount of zero
it won't interfere with SUM and would so what you want