topic Not exactly an intervalmatch in QlikView

Not exactly an intervalmatch

Sun, 11 Sep 2011 10:32:00 GMT

Hi All,

I'm trying to relate two tables where one include months the other periods in a way that result shows number of days from a given period that fall into a given month. Intervalmatch on its own doesn't work here.

Input1

---------

Emp, Month

John, 1

David, 2

Input2

---------

Emp, StartDate, EndDate

John, 2011-01-08, 2011-01-18

David, 2011-01-28, 2011-02-07

Result

---------

Emp, Month, EndDate - StartDate

John, 1, 10

David, 1, 3

David, 1, 7

Regards,

Przemek

Not exactly an intervalmatch

swuehl — Sun, 11 Sep 2011 11:16:08 GMT

Hi przemek,

I think you could use interval match if you were using a master calendar.

If you don't want to do that, I think this could calculate the days per month and Emp:

SET DateFormat='YYYY-MM-DD';

INPUT:

LOAD * INLINE [

Emp, StartDate, EndDate

John, 2011-01-08, 2011-01-18

David, 2011-01-28, 2011-02-07

Stefan, 2011-05-03, 2011-09-11

Thomas, 2011-01-01, 2011-12-31

];

OUTPUT:

LOAD Emp,

//StartDate, EndDate,

// IterNo(),

if(IterNo()=1,

if(month(EndDate)=month(StartDate), EndDate - StartDate, MonthEnd(StartDate) - StartDate-1),

if(IterNo() = (month(EndDate)-month(StartDate)+1), Day(EndDate),

Day(MonthEnd(AddMonths(StartDate,IterNo()-1)))))

as Days,

Month(StartDate) +IterNo()-1 as Month

Resident INPUT while IterNo() <= (month(EndDate)-month(StartDate)+1);

Then you maybe want to restrict the data to INPUT1, but I don't understood how month affected your result table here: In Input1, Month for David is 2 (February?), but then in your result table, David has two entries, both showing Month = 1 where I assumed you only want the second record with Month = 2.

Regards,

Stefan

Re: Not exactly an intervalmatch

jonathandienst — Sun, 11 Sep 2011 11:57:57 GMT

Hi Przemek

I was not sure if you were looking for day counts including or excluding the end date, but here is another way (for both)

EmployeeDates:
LOAD * Inline
[
    Emp, StartDate, EndDate
    John, 2011/01/08, 2011/01/18
    David, 2011/01/28, 2011/02/07
];
//------------------------------------------------------------------------------------------
// Build calendar
//------------------------------------------------------------------------------------------
tmpRange:
LOAD Min(StartDate) AS MinStart,
    Max(EndDate) AS MaxEnd
Resident EmployeeDates;
Let vMinDate = Peek('MinStart');
Let vMaxDate = Peek('MaxEnd');
Drop Table tmpRange;
Calendar:
LOAD 
    CalDate,
    Month(CalDate) AS CalMonth,
    Year(CalDate) AS CalYear;
LOAD 
    Date($(vMinDate) + IterNo() - 1) AS CalDate
AutoGenerate 1
While $(vMinDate) + IterNo() - 1 <= $(vMaxDate)
;
//------------------------------------------------------------------------------------------
// Join date range by employee to the calendar (one calendar per employee)
//------------------------------------------------------------------------------------------
Join (Calendar)
LOAD Distinct 
    Emp,
    StartDate AS Cal.StartDate,
    EndDate AS Cal.EndDate
Resident EmployeeDates;
//------------------------------------------------------------------------------------------
// EITHER --- Get the day count (exclusive of end date)
//------------------------------------------------------------------------------------------
Left Join (EmployeeDates)
LOAD Emp,
    CalMonth AS EmpMonth,
    Count(CalDate) - 1 AS DayCountEx
Resident Calendar
Where CalDate >= Cal.StartDate And CalDate <= Cal.EndDate And CalDate < MonthEnd(CalDate)
Group By Emp, CalMonth
;
//------------------------------------------------------------------------------------------
// OR --- Get the day count (inclusive of end date)
//------------------------------------------------------------------------------------------
Left Join (EmployeeDates)
LOAD Emp,
    CalMonth AS EmpMonth,
    Count(CalDate) AS DayCountInc
Resident Calendar
Where CalDate >= Cal.StartDate And CalDate <= Cal.EndDate And CalDate <= MonthEnd(CalDate)
Group By Emp, CalMonth
;

Hope that helps

Jonathan

Re: Not exactly an intervalmatch

jonathandienst — Sun, 11 Sep 2011 13:13:35 GMT

Hi Przemek

Combining Stefan's and my approach, I also came up with a simpler script:

StartEnd:
LOAD * Inline
[
     Emp, StartDate, EndDate
     John, 2011/01/08, 2011/02/01
     David, 2011/01/28, 2011/02/07
];

Output:
LOAD Emp,
     Count(DISTINCT CalDate) AS DayCountInc,
     Count(DISTINCT CalDate) - 1 AS DayCountEx,
     Month(CalDate) AS EmpMonth,
     Year(CalDate) AS EmpYear
     Group By Emp, Month(CalDate), Year(CalDate) 
;
LOAD 
     Emp,
     Date(StartDate + IterNo() - 1) AS CalDate
Resident StartEnd
While StartDate + IterNo() - 1 <= EndDate
;

Jonathan

Count(DISTINCT CalDate) AS DayCountInc,

Not exactly an intervalmatch

swuehl — Sun, 11 Sep 2011 13:36:47 GMT

Hi Jonathan,

nice scripting

I noticed a (possible) problem with your DayCountEx in both scripts: You are removing one day from the count for every month, so if the Emps time period span more than 2 months, the count will be incorrect (and for 2 month they are only correct if you want to exclude start and end date, which don't match the sample result. I assumed from the example results, that one want only the start date to be excluded from the count.)

Regards,

Stefan

Not exactly an intervalmatch

Sun, 11 Sep 2011 13:47:28 GMT

Thanks a lot both of you, guys. Very helpful answers those were. I'm also now thinking of creating a little bit easier model related to the above one i.e.

Input

-------

Emp, StartDate, EndDate

John, 2011-01-31, 2011-02-01

David, 2011-02-08, 2011-02-08

Result

---------

Emp, CalendarDate

John, 2011-01-31

John, 2011-02-01

David, 2011-02-08

How would you implement the CalendarDate to represent each day from the period?

Regards,

Przemek

Re: Not exactly an intervalmatch

swuehl — Sun, 11 Sep 2011 14:31:38 GMT

So you want a record for each day of the period (I don't see this in your Result table, but that's how I read your last sentence)?

Just reuse Jonathans last Load:

LOAD

Emp,

Date(StartDate + IterNo() - 1) AS CalDate

Resident Input

While StartDate + IterNo() - 1 <= EndDate

;

(Or think about a master calendar and interval match).

Bye,

Stefan

Re: Not exactly an intervalmatch

jonathandienst — Sun, 11 Sep 2011 17:56:33 GMT

You did not specify that employees could have multiple entries in your original post , bur here goes. The main thing is to identify which employee record is being processed, so I add a RowKey field as the first step. Pretty much unchanged after that. The script is now:

StartEnd:
LOAD * Inline
[
    Emp, StartDate, EndDate
    John, 2011/01/08, 2011/01/12
    John, 2011/02/04, 2011/02/09
    John, 2011/02/11, 2011/02/18
    David, 2011/01/28, 2011/02/07
];
Join (StartEnd)
LOAD *, RowNo() AS RowKey Resident StartEnd;
Output:
LOAD Emp,
    CalDate,
    RowKey,
    Month(CalDate) AS CalMonth,
    Year(CalDate) AS CalYear
;
LOAD 
    Emp,
    RowKey,
    Date(StartDate + IterNo() - 1) AS CalDate
Resident StartEnd
While StartDate + IterNo() - 1 <= EndDate
;

Jonathan

Re: Not exactly an intervalmatch

jonathandienst — Sun, 11 Sep 2011 18:00:08 GMT

Stefan

swuehl wrote:
I noticed a (possible) problem with your DayCountEx in both scripts: You are removing one day from the count for every month, so if the Emps time period span more than 2 months, the count will be incorrect (and for 2 month they are only correct if you want to exclude start and end date, which don't match the sample result. I assumed from the example results, that one want only the start date to be excluded from the count.)

You are quite right - I did not test this adequately. I added a check for the month of the CalDate and the month of the EndDate, and only when they are equal then subtract 1 from the count - that fixed the problem.

Jonathan

Not exactly an intervalmatch

Sun, 11 Sep 2011 18:34:20 GMT

I've added StartDate and End Date to the final load and it does the same. Anyway, many thanks for the reply.