topic Re: Numbering events by time in QlikView

Numbering events by time

Thu, 03 Nov 2016 10:48:23 GMT

Hello,

once again got a really hard nut to crack:

Let's assume we have students. These students have Exam Attempts.

So we have a table like this:

Student	Exams (Attempt)	Date
Student1	Math	19.10.2015
Student1	Math	24.10.2015
Student1	Math	30.10.2015
Student2	Math	20.10.2015
Student3	Math	19.10.2015
Student3	Math	28.10.2015

Now what we would like to do is change the Text Math to Attempt1, Attempt2, Attempt3 etc.

So the final table should change like the following:

Student	Exams (Attempt)	Date
Student1	Attempt 1	19.10.2015
Student1	Attempt 2	24.10.2015
Student1	Attempt 3	30.10.2015
Student2	Attempt 1	20.10.2015
Student3	Attempt 1	19.10.2015
Student3	Attempt 2	28.10.2015

The dates of the exams are random. So it means that a math test for one student can be on another date for another student.

So at the moment we are pretty clueless how to procede. Maybe you can give us a hint about a good function we could use or in general how to progress.

Re: Numbering events by time

tresB — Thu, 03 Nov 2016 10:54:34 GMT

Try like:

Load

Student,

'Attempt' & AutoNumber(RowNo(), Student) as Exam(Attempt),

Date

From <>;

Re: Numbering events by time

Thu, 03 Nov 2016 12:05:15 GMT

Thanks! Works like a charm!

Re: Numbering events by time

Fri, 04 Nov 2016 10:06:13 GMT

Dear Tresesco Biswas,

it seems to work if we only have one kind of Exam(like Math). But if we have multiple it does not work anymore:

Here is our current code:

Events:

Load

Student,

if(Exams='Math','Math' & AutoNumber(RowNo(),Student),

) as Events,

Date

resident Datatable

WHERE Exams='Math';

;

CONCATENATE

Load

Student,

if(Exams='Biology','Biology' & AutoNumber(RowNo(),Student),

) as Events,

Date

resident Datatable

WHERE Exams='Biology';

;

CONCATENATE

Load

Student,

if(Exams='Chemistry','Chemistry' & AutoNumber(RowNo(),Student),

) as Events,

Date

resident Datatable

WHERE Exams='Chemistry';

;

CONCATENATE

Load

Student,

if(Exams='Physics','Physics' & AutoNumber(RowNo(),Student),

) as Events,

Date

resident Datatable

WHERE Exams='Physics';

The problem is - if we have a student and he has only three Math courses then he has

Math1

Math2

Math3

That is correct.

But if he has 3 Math courses and 2 Biology courses he has:

Math1

Biology2

Math3

Math4

Biology5

Correct would be:

Math1

Biology1

Math2

Math3

Biology2

So we dont know exactly what to do - but one idea would be to substract the amount of Math courses for a student from the Atuonumber for Biology... something like this:

Load

Student,

if(Exams='Biology','Biology' & (AutoNumber(RowNo(),Student)-Count(Math???),

) as Events,

Date

resident Datatable

WHERE Exams='Biology';

;

Unfortunately we dont know if this is the right way and we do not know how to formulate that subquery (if this would be the right way to approach the problem).

So any help apreciated!

Re: Numbering events by time

MarcoWedel — Sat, 05 Nov 2016 23:45:17 GMT

sample data

Student	Exams (Attempt)	Date
Student1	Math	19.10.2015
Student1	Math	24.10.2015
Student1	Biology	30.10.2015
Student2	Math	20.10.2015
Student3	Math	19.10.2015
Student3	Math	28.10.2015
Student1	Physics	15.10.2015
Student3	Biology	19.10.2015
Student2	Physics	25.10.2015
Student1	Math	27.10.2015
Student3	Physics	23.10.2015
Student4	Math	05.10.2015
Student1	Biology	09.10.2015
Student3	Physics	12.10.2015
Student4	Math	01.10.2015
Student1	Physics	03.10.2015
Student4	Physics	07.10.2015
Student4	Math	26.10.2015
Student1	Biology	24.10.2015
Student4	Physics	17.10.2015

Re: Numbering events by time

MarcoWedel — Sun, 06 Nov 2016 00:06:20 GMT

Hi,

the trick is to use a combination of student and exam as second Autonumber() parameter (AutoID), because you're counting per student and exam instead of per student only. So one example extending Tresesco's solution might be:

tabExams:
LOAD RecNo() as ID, *   
FROM [https://community.qlik.com/thread/238549] (html, codepage is 1252, embedded labels, table is @3);

Left Join (tabExams)
LOAD ID,
    [Exams (Attempt)]&AutoNumber(ID,Student&'/'&[Exams (Attempt)]) as Events
Resident tabExams
Order By Date;

hope this helps

regards

Marco