topic Re: Peek doubt in QlikView

Peek doubt

jyothish8807 — Sun, 09 Nov 2014 18:05:18 GMT

Hi All,

I am confused with peek function.Can any one please explain me step by step how it is getting evaluated?

Date(If( Currency=Peek(Currency),Peek(FromDate) - 0.1,'1/1/2014)) as ToDate

how is Currency=Peek(Currency) is being checked?

Peek pulls the last entry as i know.Please any one can explain with example.

Regards

Re: Peek doubt

Sun, 09 Nov 2014 18:30:29 GMT

Date(If( Currency=Peek(Currency),Peek(FromDate) - 0.1,'1/1/2014)) as ToDate

if (currency=peek(currency)) means here in currency table you are going to select one value if that value equal to peek(currency) means in currency table last entry then date(peek(fromdate) -o.1 ) else date(1/1/2014)

still if ur in confusion put expression in front end text box and check by step by step .

here date function tell how to show date

Re: Peek doubt

jyothish8807 — Sun, 09 Nov 2014 18:37:41 GMT

Thanks for reply Manoj,

Suppose i have 6 entries for Currency then how is it being compared.

eg.

Currency

Now if i write currency=peek(currency) how is it being compared?

a=c

b=c

c=c

Am i right?

Regards

Re: Peek doubt

Sun, 09 Nov 2014 18:40:35 GMT

qlikview stores data uniquely only , thats is the beauty of qlikview

no worries about duplicate data just go through that expression u will get output

Re: Peek doubt

jyothish8807 — Sun, 09 Nov 2014 18:50:14 GMT

I am getting the output, but want to know how is it evaluated. Cant understand the operation.

Regards

Re: Peek doubt

Sun, 09 Nov 2014 18:57:22 GMT

see if u have common data in database and while loading data in qlikview ,by default qlikview stores data unique only.

as per ur example if u have

Currency

but this stores in qlikview like

currency

only but in backend it relation ship with a=c,a=c,b=c,b=c,c=c

thats we can see so that we can say qlikview is an associate in memory techknowledgy . it stores data in ram

Re: Peek doubt

maxgro — Sun, 09 Nov 2014 21:50:01 GMT

add a unique field to see the peek on all records

Tmp:

load * inline [

Currency

];

Final:

NoConcatenate

load rowno() as id, Currency,

peek(Currency) as PeekCurrency,

Currency=peek(Currency) as CurrencyEqPeekCurrency

Resident Tmp;

drop table Tmp;

Re: Peek doubt

MarcoWedel — Sun, 09 Nov 2014 22:32:32 GMT

Hi,

one example:

LOAD *,
    Date(If( Currency=Peek(Currency),Peek(FromDate) - 0.1,'1/1/2014')) as ToDate
Inline [
Currency,FromDate
a,1/10/2014
a,1/20/2014
b,2/11/2014
b,2/21/2014
b,3/12/2014
c,3/22/2014
];

ToDate is calculated this way:

If the Currency value in one loaded record is equal to the previous loaded value (the record before) then ToDate gets the FromDate value of this previous record minus 0.1 days (= 2.4 hours = 2hours 24minutes).

If the Currency value in one loaded record is not equal to the previous loaded value then ToDate gets January 1st 2014 as Date value.

The subtraction of 0.1 from the previous FromDate creates a fractional part in the date field, so it's becoming a timestamp rather than an integer date value. The time part equals 9:36 pm.

hope this helps

regards

Marco