What SQL can I use to retrieve counts from my payments data?
Count criteria: A \"true\" count, by month-year, of the number of students (indexed by a unique Student ID) at each School by School Service Type.
I am currently usi
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Here's one way to tackle it. For sample data in a table named [Payments]
Payment Row Student ID School School Service Type PaymentStartDate PaymentEndDate ----------- ---------- ------ ------------------- ---------------- -------------- 1 001 ABC ED 2010-01-02 2012-02-04 2 001 ABC ED 2010-01-02 2010-01-05 3 001 ABC ED 2010-04-02 2010-05-05 4 001 DEF EZ 2010-01-02 2012-02-04 5 001 RR 2012-02-02 2012-02-03 6 002 ABC ED 2010-02-02 2011-02-03 7 002 ABC EZ 2010-02-02 2010-06-03 8 002 GHI ED 2011-02-04 2012-02-04 9 003 ABC ED 2011-02-02 2012-02-03 10 003 DEF ED 2010-01-02 2010-08-03 11 003 RR 2011-02-02 2011-02-03 12 004 RR 2011-02-02 2011-02-03 13 005 GHI ED 2010-08-02 2011-02-04 14 006 GHI ED 2010-08-02 2010-08-02if we create a saved query in Access named [PaymentsYearMonth]
SELECT [Student ID], School, [School Service Type], (Year(PaymentStartDate) * 100) + Month(PaymentStartDate) AS StartYYYYMM, (Year(PaymentEndDate) * 100) + Month(PaymentEndDate) AS EndYYYYMM FROM Paymentsit will give us
Student ID School School Service Type StartYYYYMM EndYYYYMM ---------- ------ ------------------- ----------- --------- 001 ABC ED 201001 201202 001 ABC ED 201001 201001 001 ABC ED 201004 201005 001 DEF EZ 201001 201202 001 RR 201202 201202 002 ABC ED 201002 201102 002 ABC EZ 201002 201006 002 GHI ED 201102 201202 003 ABC ED 201102 201202 003 DEF ED 201001 201008 003 RR 201102 201102 004 RR 201102 201102 005 GHI ED 201008 201102 006 GHI ED 201008 201008To generate the Year/Month pairs that the data covers, we can use a table named [MonthNumbers]
MonthNumber ----------- 1 2 3 4 5 6 7 8 9 10 11 12and a table named [YearNumbers] which covers every year that might possibly appear in the data. For safety one might include every year from, say, 1901 to 2525, but for illustration we'll just use
YearNumber ---------- 2009 2010 2011 2012 2013Now we can create a saved query named [MonthsToReport] to give us the rows that might have results
SELECT yn.YearNumber, mn.MonthNumber, (yn.YearNumber * 100) + mn.MonthNumber AS YYYYMM FROM YearNumbers AS yn, MonthNumbers AS mn WHERE ((yn.YearNumber * 100) + mn.MonthNumber)>=DMin("StartYYYYMM","PaymentsYearMonth") AND ((yn.YearNumber * 100) + mn.MonthNumber)<=DMax("EndYYYYMM","PaymentsYearMonth")Sorted by Year and Month that would look like
YearNumber MonthNumber YYYYMM ---------- ----------- ------ 2010 1 201001 2010 2 201002 2010 3 201003 2010 4 201004 2010 5 201005 2010 6 201006 2010 7 201007 2010 8 201008 2010 9 201009 2010 10 201010 2010 11 201011 2010 12 201012 2011 1 201101 2011 2 201102 2011 3 201103 2011 4 201104 2011 5 201105 2011 6 201106 2011 7 201107 2011 8 201108 2011 9 201109 2011 10 201110 2011 11 201111 2011 12 201112 2012 1 201201 2012 2 201202Now to create a query that gives us distinct instances of Year/Month/Student/School/Type
SELECT DISTINCT mtr.YearNumber, mtr.MonthNumber, pym.[Student ID], pym.School, pym.[School Service Type] FROM MonthsToReport AS mtr INNER JOIN PaymentsYearMonth AS pym ON mtr.YYYYMM>=pym.StartYYYYMM AND mtr.YYYYMM<=pym.EndYYYYMM...wrap that in an aggregation query to count up the (now unique) [Student ID] values
SELECT YearNumber, MonthNumber, School, [School Service Type], COUNT(*) AS CountOfStudents FROM ( SELECT DISTINCT mtr.YearNumber, mtr.MonthNumber, pym.[Student ID], pym.School, pym.[School Service Type] FROM MonthsToReport AS mtr INNER JOIN PaymentsYearMonth AS pym ON mtr.YYYYMM>=pym.StartYYYYMM AND mtr.YYYYMM<=pym.EndYYYYMM ) AS distinctQuery GROUP BY YearNumber, MonthNumber, School, [School Service Type]and then use that as the FROM subquery in our crosstab query
TRANSFORM Nz(First(CountOfStudents),0) AS n SELECT YearNumber, MonthNumber, School FROM ( SELECT YearNumber, MonthNumber, School, [School Service Type], COUNT(*) AS CountOfStudents FROM ( SELECT DISTINCT mtr.YearNumber, mtr.MonthNumber, pym.[Student ID], pym.School, pym.[School Service Type] FROM MonthsToReport AS mtr INNER JOIN PaymentsYearMonth AS pym ON mtr.YYYYMM>=pym.StartYYYYMM AND mtr.YYYYMM<=pym.EndYYYYMM ) AS distinctQuery GROUP BY YearNumber, MonthNumber, School, [School Service Type] ) AS countQuery GROUP BY YearNumber, MonthNumber, School PIVOT [School Service Type]returning
YearNumber MonthNumber School ED EZ RR ---------- ----------- ------ -- -- -- 2010 1 ABC 1 0 0 2010 1 DEF 1 1 0 2010 2 ABC 2 1 0 2010 2 DEF 1 1 0 2010 3 ABC 2 1 0 2010 3 DEF 1 1 0 2010 4 ABC 2 1 0 2010 4 DEF 1 1 0 2010 5 ABC 2 1 0 2010 5 DEF 1 1 0 2010 6 ABC 2 1 0 2010 6 DEF 1 1 0 2010 7 ABC 2 0 0 2010 7 DEF 1 1 0 2010 8 ABC 2 0 0 2010 8 DEF 1 1 0 2010 8 GHI 2 0 0 2010 9 ABC 2 0 0 2010 9 DEF 0 1 0 2010 9 GHI 1 0 0 2010 10 ABC 2 0 0 2010 10 DEF 0 1 0 2010 10 GHI 1 0 0 2010 11 ABC 2 0 0 2010 11 DEF 0 1 0 2010 11 GHI 1 0 0 2010 12 ABC 2 0 0 2010 12 DEF 0 1 0 2010 12 GHI 1 0 0 2011 1 ABC 2 0 0 2011 1 DEF 0 1 0 2011 1 GHI 1 0 0 2011 2 0 0 2 2011 2 ABC 3 0 0 2011 2 DEF 0 1 0 2011 2 GHI 2 0 0 2011 3 ABC 2 0 0 2011 3 DEF 0 1 0 2011 3 GHI 1 0 0 2011 4 ABC 2 0 0 2011 4 DEF 0 1 0 2011 4 GHI 1 0 0 2011 5 ABC 2 0 0 2011 5 DEF 0 1 0 2011 5 GHI 1 0 0 2011 6 ABC 2 0 0 2011 6 DEF 0 1 0 2011 6 GHI 1 0 0 2011 7 ABC 2 0 0 2011 7 DEF 0 1 0 2011 7 GHI 1 0 0 2011 8 ABC 2 0 0 2011 8 DEF 0 1 0 2011 8 GHI 1 0 0 2011 9 ABC 2 0 0 2011 9 DEF 0 1 0 2011 9 GHI 1 0 0 2011 10 ABC 2 0 0 2011 10 DEF 0 1 0 2011 10 GHI 1 0 0 2011 11 ABC 2 0 0 2011 11 DEF 0 1 0 2011 11 GHI 1 0 0 2011 12 ABC 2 0 0 2011 12 DEF 0 1 0 2011 12 GHI 1 0 0 2012 1 ABC 2 0 0 2012 1 DEF 0 1 0 2012 1 GHI 1 0 0 2012 2 0 0 1 2012 2 ABC 2 0 0 2012 2 DEF 0 1 0 2012 2 GHI 1 0 0讨论(0)
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